Question

In which sentence are all pronouns used as objects of a preposition used correctly? A. Michael sat at the table with they and Harry. B. Lily walked to the park with she and I. C. Tracey pushed the cart between I and Dad. D. Between you and me, we can move this old sofa.

Answer 1

In which sentence are all pronouns used as objects of a preposition used correctly?

C. Tracey pushed the cart between I and Dad.

The object of a preposition can be a noun or pronoun.  In sentence C, between  would be the preposition, and I and Dad would  be the object of the preposition. The remaining sentences are not examples of pronouns used as objects of preposition. Sentences A and B use the objective cases incorrectly, it should be: them instead of they, and her instead of she. Sentence C uses between you and me  as subject and not as object of preposition.  

Answer 2

D. Between you and me, we can move this old sofa. This is the sentence in which all the pronouns are used as objects of a preposition. See the underlined structure and the categories below:

Between: preposition

you: objective pronoun

me: objective pronoun