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

A demonstrative pronoun is used to point to specific things or people and includes terms like "this," "that," "these," and "those." In this context, "this" serves as a demonstrative pronoun because it specifies a particular item or individual that is in proximity to the speaker. For example, one might say, "This is my book," indicating a specific book that is near. The other options, while they serve important grammatical roles, do not fit the definition of a demonstrative pronoun. "Him" is a personal pronoun, "happy" is an adjective describing a quality or state of being, and "teacher" is a noun that identifies a person; none of these function in the same way as "this" does in directing attention to a particular entity.