Answer: "Who", "which" and "where" can be used as relative pronouns.
Step-by-step explanation: A relative pronoun is pronoun that introduces a relative clause, that is to say a dependent clause which adds information about an antecedent. There are many relative pronouns: two of them are "who", which refers to a person, and "which", which refers to a thing or an animal. Moreover, although "where" is a relative adverb, it can also be used as a relative pronoun. When "where" is used as a relative pronoun, it provides additional information about a place. An example of this is the sentence "This is the hotel where we stayed last summer".