A prepositional phrase is a group of words that lacks either a verb or a subject, and that functions as a unified part of speech. It normally consists of a preposition and a noun or a preposition and a pronoun.
The type of clause that the clause or the phrase does have is in letter C. adverbial clause. Adverbial clause is a dependent clause that functions as an adverb; that is , the entire clause modifies a verb, and adjective, or another adverb. I hope you are satisfied with my answer and feel free to ask for more
