Which sentence contains an example of a demonstrative pronoun?

Sure, here are some sentences:

1. "This is my favorite book."
2. "These are my friends."
3. "That is a beautiful painting."
4. "Those are some interesting ideas."

In these sentences, "this", "these", "that", and "those" are demonstrative pronouns. They are used to point to and identify specific things or people. For example, in the first sentence, "this" is used to point to a specific book that is close to the speaker. In the second sentence, "these" is used to point to a group of friends that are close to the speaker. In the third sentence, "that" is used to point to a specific painting that is farther away from the speaker. In the fourth sentence, "those" is used to point to a group of ideas that are farther away from the speaker.