Instructions. Select the correct preposition from the drop down menu.
Explanation
Who, whom, which, and that can function as the object of a prepositions (e. g. to, for, at, on, about, from, etc.) when they occur in adjective clauses.
I saw the movie that you told me about. That is the object of about.
Who was the person that you talked to? That is the object of to.
The relative pronoun can be omitted when it functions as the object of the preposition.
I saw the movie you told me about. Who was the person you talked to?