Final answer:
The word 'backpack' is a noun.
Step-by-step explanation:
In the given options, the word 'backpack' is a noun. Nouns are words that represent people, places, things, or ideas. They can be concrete, such as 'backpack,' which refers to a physical object, or abstract, such as 'love,' which represents a concept or feeling.
Learn more about Types of words in English