Answer:
The sentence The man in the gray suit tipped his hat contains a b) prepositional phrase used as an adjective.
Explanation:
A prepositional phrase is a group of words made up of a preposition and its object that may include any other word that modifies the object. Prepositional phrases can function as a noun, as an adverb or as an adjective, like in this case. The prepositional phrase in the gray suit, introduced by the preposition in, is functioning as a adjective, since it is modifying the noun man.
