Final answer:
The pronoun "My" in the sentence "My favorite childhood game was Duck, Duck, Goose," is in the possessive case (option C) since it shows ownership of "favorite childhood game."
Step-by-step explanation:
The question refers to the pronoun "My" in the phrase "My favorite childhood game was Duck, Duck, Goose," and asks to identify its case. In English grammar, pronouns have three cases: subjective, objective, and possessive. Subjective case pronouns function as the subject of a sentence (e.g., "I like pizza").
Objective case pronouns function as objects within a sentence, either as the object of a verb or of a preposition (e.g., "Laura gave him the baseball."). Possessive case pronouns show ownership (e.g., "The cat picked up its toy"). The pronoun "My" in the given sentence is showing ownership or relation to "favorite childhood game," which means it is in the possessive case (option C).