Hello, I would like to know what a PRO-infinitive construction is. I searched Google for an explanation and I didn't find any example or anything clear. My Longman grammar book says nothing about it either.

I have the following question to answer:
Specify the type of the infinitival construction in the following complex sentence:
She wants to be rewarded.
a. PRO-infinitive
b. For to-infinitive
c. Nominative plus Infinitive Construction
d. Accusative plus Infinitive Construction

My initial answer was Nominative plus Infinitive Construction because "want" is a verb of liking and disliking but, I'm not sure if it applies in this context.

By excluding the other options I'm left with PRO-infinitive and unfortunately I can't find any info on this type of construction. :(