Answer:
Object
Explanation:
A prepositional phrase is a phrase that consists of a preposition, the object of the preposition (a noun, pronoun, gerund, or clause) and, it may have a modifier of the object (E.g. the). This type of phrase can act as an adjective or an adverb: it modifies a word or group of words and relates that word or group of words to the preposition's object.
Here's an example:
The students found the illustrations of the problem helpful.
Preposition=of; modifier of the object=the; object=problem.
Here, the prepositional phrase works as an adjective because it modifies the noun "the illustrations", and at the same time it relates that noun to the preposition's object "problem"
