Choose the sentence that contains an adjectival prepositional phrase.
a. the shoe store across the street recently opened.
b. the game begins within an hour.
c. the tired campers rested underneath the tent.
d. the dog ran around the table.

The answer is letter A. The shoe store across the street recently opened.

Prepositional phrases are used in a sentence either as an adjective or an adverb.
Adjectival prepositional phrase tells which one, how much, how many or what kind. It follows nouns it modifies not like adjectives which go before the nouns it modifies. On the other hand, adverb prepositional phrase tells why, or in what circumstances and or in what way, like intensifiers. It modifies adjectives and adverbs should go after the words it modifies.