Interrogative Pronoun : Pronouns which are for asking questions are called Interrogative Pronoun.
Who is there ?
Who are you ?
About whom are you talking?
Who are you talking about?
Whom do you want HWho do you want?
Whose is this book ?
Which is the house ?
Which do you prefer, tea or coffee ?
What is the matter ?
What do you want ?
Learn more about Pronoun and Types of Pronouns here.