This is the original sentence: In a feeding frenzy, the pigeons descended upon the breadcrumbs that the kindly old man on the park bench continued to toss.
The correct answer is the prepositional phrase "on the park bench" acts as an adjectival phrase.
A is incorrect because a prepositional phrase cannot be a gerund phrase too. B is incorrect because a prepositional phrase cannot be a verb phrase as well. D is incorrect because 'to toss' is not a prepositional phrase, but rather an infinitive.
