Answer: B. According to the paper
Step-by-step explanation:
A preposition is a word that indicates a relationship between other words. Examples of prepositions are: at, in, on, to, for, etc.
A prepositional phrase is constituted by a preposition and its object (complement). In the sentence we are analyzing here, the prepositional phrase is "according to the paper", in which "according to" is the preposition that indicates something is reported by someone or something else, and "the paper" is the preposition's object.