Which one of these sentences contains a prepositional phrase?

AYou may think otherwise, but what I tell you is true.
BWhere did you find the papers that I lost?
CTrolls live under bridges; elves do not.
DTo be, or not to be: that is the question.

Verified Answer :

There is only one prepositional phrase among these options, and that would be under bridges. The correct answer is C.
A prepositional phrase is the one which follows a preposition, in this case the word under.