Which of the following is an example of a demonstrative pronoun?

A demonstrative pronoun is used to indicate specific people or things and to show their relative position in space or time. The word "this" is one such pronoun that points to a singular noun that is nearby, either in a physical sense or in the context of writing or conversation.

For example, if someone says, "This is my favorite book," the word "this" refers directly to a specific book that is close to the speaker. It clearly helps the listener understand which book is being discussed. Demonstrative pronouns can also include "that," "these," and "those," which further help in identifying and differentiating between singular and plural objects, as well as their proximity.

In contrast, the other options do not serve the same purpose. "I" and "she" are personal pronouns, while "they" is a plural personal pronoun. These types of pronouns do not indicate a specific object or location in the same way demonstrative pronouns do. Therefore, "this" stands out as the correct choice to fulfill the criteria of being a demonstrative pronoun.