In English grammar, pronouns are used as substitutes for nouns and noun phrases. We use eight kinds of pronouns in total- Indefinite, Personal, Reflexive, Possessive, Demonstrative, Relative, Interrogative, and Emphatic. Indefinite pronouns are those which do not strictly refer to anything. Possessive pronouns mean ownership of something, for example, ' That Alpaca is mine'. Personal pronouns simply replace the name of a person or an object. Demonstrative pronouns indicate the noun in the sentence. So option A is the correct option.