LINQ select List where sub-list contains item from another list
<p>I can't wrap my head around how to create this query. I need to select the items in List 1, if the items Cats list contains a Cat object matching the ID of one of the Cats in List2. Is this possible? Thank you</p>

<pre><code>List1&lt;pet&gt; List1 = new List&lt;pet&gt;(100);
List2&lt;cat&gt; List2 = new List&lt;cat&gt;(30);

//populate lists, some of the items in List2 (cat) will be in the List1 items Cats list

//classes
class pet{
   string ID;
   List&lt;cat&gt; Cats;
}

class cat {
   string ID;
   string name;
}
</code></pre>