when this and that are used to modify nouns, they are treated as

a. pronouns

b. adjectives

b. Adjectives

Explanation:
In this case, “this” and “that” would be adjectives because they are adding clarity to the nouns.
For example, “this cat”. In that instance, “this” is not functioning as a noun, it is instead specifying which cat the speaker is referring to. You can take “this” or “that” and have it modify any noun, and it would still be an adjective.

Abiography is a description of a real person's life, including factual details as well as stories from the person's life. biographies usually include information about the subject's personality and motivations, and other kinds of intimate details excluded in a general overview or profile of a person's life.