Answer:
Adjective
Step-by-step explanation:
A prepositional phrase is a group of words that consists of a preposition, its object, and the words that modify the object. Prepositions are words that connect other words within the sentence and express the relationship between them.
The prepositional phrase used in the given sentence is in the blue suit. The preposition is in, suit is its object, and the words that modify the object are the and blue.
This prepositional phrase is an adjective prepositional phrase. This means that it functions as an adjective. Adjectives are words that modify nouns, and this phrase modifies the noun gentleman.