Answer: C. Collective noun.
Explanation: A noun is a word that names a person, a place, an object or a thing. There are different kinds of nouns, proper nouns are used to name specific persons, places or things, common nouns are used to name general things (not specific ones), collective nouns are used to name a number of people or things and compound nouns are names that are formed for two or more words. "The staff" represents a collective noun because it refers to a group of people.
