The appropriate answers are: We, Theirs, He. In the first and third examples, the query seeks to replace proper nouns (Cari and I, Mr. Chen) with subject pronouns (We, He). In the second instance, the objective is to substitute proper nouns (David and Jessica) along with the possessive communicated through the apostrophe with a possessive form (Theirs). The fundamental meaning is preserved without requiring additional context. A subject pronoun functions as the sentence subject responsible for the action, whereas a possessive pronoun denotes ownership more broadly, often used alongside a noun indicating the object of ownership.
