The personal pronoun that best completes the sentence and how it is used, is "us" and is used as an object of a preposition. The correct answer is option D. The complete sentence would be: Among the three of us, Kevin was the tallest. The pronoun "us" is an objective pronoun. Objective pronouns are pronouns that are used as a direct object, indirect object and object of the preposition. In this case, it is the object of a preposition because it is introduced by the preposition "among".