Which of the following is NOT a type of noun?

The correct answer is A, which is "Adjective." This is because an adjective is a part of speech that describes or modifies a noun, rather than being a noun itself. Nouns are words that represent people, places, things, or ideas, while adjectives provide more information about those nouns.

In contrast, abstract nouns refer to concepts or ideas that cannot be physically touched, such as "freedom" or "happiness." Collective nouns are terms that describe a group of individuals or things, like "team" or "flock." Proper nouns are specific names of people, places, or organizations, like "Eiffel Tower" or "Jennifer." Each of these is a specific type of noun, thereby distinguishing them from adjectives, which serve a different function in language.