Get random element from array in MongoDB
<p>Here is my database structure </p>

<pre><code>{
     "_id" : ObjectId("576155226d1d298c2cc3edca"),
     "questionLibrary" : {
             "technologyName" : "CSS",
             "questions" : [
                     {
                             "correctanswer" : {
                                     "A1" : "CSS1"
                             },
                             "answeroption" : {
                                     "A4" : "CSS1",
                                     "A3" : "CSS1",
                                     "A2" : "CSS1",
                                     "A1" : "CSS1"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS1"
                     },
                     {
                             "question" : "CSS2",
                             "tags" : "CSS",
                             "answeroption" : {
                                     "A1" : "CSS2",
                                     "A2" : "CSS2",
                                     "A3" : "CSS2",
                                     "A4" : "CSS2"
                             },
                             "level" : "Amature",
                             "correctanswer" : {
                                     "A1" : "CSS2"
                             }
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS3"
                             },
                             "answeroption" : {
                                     "A4" : "CSS3",
                                     "A3" : "CSS3",
                                     "A2" : "CSS3",
                                     "A1" : "CSS3"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS3"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS4"
                             },
                             "answeroption" : {
                                     "A4" : "CSS4",
                                     "A3" : "CSS4",
                                     "A2" : "CSS4",
                                     "A1" : "CSS4"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS4"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS5"
                             },
                             "answeroption" : {
                                     "A4" : "CSS5",
                                     "A3" : "CSS5",
                                     "A2" : "CSS5",
                                     "A1" : "CSS5"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS5"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS6"
                             },
                             "answeroption" : {
                                     "A4" : "CSS6",
                                     "A3" : "CSS6",
                                     "A2" : "CSS6",
                                     "A1" : "CSS6"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS6"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS7"
                             },
                             "answeroption" : {
                                     "A4" : "CSS7",
                                     "A3" : "CSS7",
                                     "A2" : "CSS7",
                                     "A1" : "CSS7"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS7"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS8"
                             },
                             "answeroption" : {
                                     "A4" : "CSS8",
                                     "A3" : "CSS8",
                                     "A2" : "CSS8",
                                     "A1" : "CSS8"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS8"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS9"
                             },
                             "answeroption" : {
                                     "A4" : "CSS9",
                                     "A3" : "CSS9",
                                     "A2" : "CSS9",
                                     "A1" : "CSS9"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS9"
                     },
                     {
                             "correctanswer" : {
                                     "A1" : "CSS10"
                             },
                             "answeroption" : {
                                     "A4" : "CSS10",
                                     "A3" : "CSS10",
                                     "A2" : "CSS10",
                                     "A1" : "CSS10"
                             },
                             "level" : "Amature",
                             "tags" : "CSS",
                             "question" : "CSS10"
                     }
             ]
     },
     "__v" : 3
}
</code></pre>

<p>From the question array, I want to get a random object (random question) each time I fire the query. </p>

<p>I don't want to collect all the objects at a time and manupulate them in node. Is it possible to write a query so that it will return a random object each time?</p>