Final answer:
None of the options provided ('Book,' 'Sister,' 'Cheese,' 'Parents') are personal pronouns, but 'Sister' and 'Parents' could be replaced by personal pronouns such as 'she' and 'they'. Personal pronouns include 'I, we, you, he, she, it, they' (subjective case), 'me, us, you, him, her, it, them' (objective case), and possessive forms like 'my/mine, our/ours, your/yours, his/her/hers, its, their/theirs'.
Step-by-step explanation:
A personal pronoun is a word used in place of a noun that refers to people or things. The options given do not include a personal pronoun directly, but it is implied that one must choose which could be replaced by a personal pronoun. The options are 'Book,' 'Sister,' 'Cheese,' and 'Parents.' Of these, 'Sister' and 'Parents' can be replaced by personal pronouns such as 'she' for sister or 'they' for parents.
However, in the strict sense of the provided options, none of them is a personal pronoun. Yet to understand the concept, you should know that there are different cases for personal pronouns, such as the subjective case (I, we, you, he, she, it, they), which function as subjects in a sentence, the objective case (me, us, you, him, her, it, them), which serve as objects in a sentence, and the possessive case (my/mine, our/ours, your/yours, his/her/hers, its, their/theirs), which show ownership.