What are the four italian interrogative pronouns?

The four italian interrogative pronouns are:

• Chi (who), it's invariable and refers only to people,singular or plural.
• Che cosa (what) still invariable and refers just to things or concepts.
• Quale (which), invariable in genre but has different forms for singular and plural (qual, quali).
• Finally Quanto (how many, how much)it is variable in genre and number (quanti,quante, quanta), used with people or things.