Answer:
4. with an increasing number
Explanation:
A prepositional phrase is a modifying phrase consisting of a preposition and its object.
The verb here is "had given"; this is past perfect: it's a perfect tense, because it has a past participle with the -ed ending ("given") and it's the past perfect because the auxiliary verb is the past form of "have": had.
In “a red hat,” the adjective “red” is a modifier describing the noun “hat.” In “They were talking loudly,” the adverb “loudly” is a modifier of the verb “talking.”