It is important to understand the parts of speech to be able to correctly determine how a word functions in a sentence, not just grammatically, but also in meaning. It is also important to keep in mind that the same word may function as more than just one part of speech, according to the context. There are eight parts of speech: noun, pronoun, verb, adjective, adverb, preposition, conjunction, and interjection. As we can see, option B. sentence is not included. As a matter of fact, a sentence is usually the result of the parts of speech being in use.
