I believe that there are three prepositional phrases but if you would like to do it yourself instead of taking my word for it. a prepositional phrase is a modifying phrase consisting of a preposition and its object.
And a preposition is a word governing, and usually preceding, a noun or pronoun and expressing a relation to another word or element in the clause, as in “the man on the platform,” “she arrived after dinner,” “what did you do it for ?”