Which word is the indefinite pronoun in this sentence?
chris yelled to us from the dock, saying, "something isn't right with that boat out in the water."
a. chris
b. something
c. us
d. that

Indefinite pronouns are pronouns that does not refer to something or someone in particular. It creates a vague image of the subject, object, or complement. In this sentence, there are two pronouns: something, and us. Let's analyze the choices.

(a) Chris is a name of a person. Hence, it is a noun and not a pronoun.
(b) Something is perfect example of an indefinite pronoun. It doesn't clearly answer the question, "What?"
(c) Us is a pronoun. However, it is a personal pronoun in the first person plural case.
(d) That can be a relative pronoun. However, it's used as a demonstrative adjective in the sentence. It implies the location of the book.