Answer: A) Noun.
Explanation: To be able to identify the different parts of the speech, we need to know their definitions, a noun is a word that is a name, it can be the name of a place, a person or an object. A verb is a word that expresses an action, an adjective is a word that modifies a noun and an adverb usually modifies a verb, an adjective or other adverbs. In the given sentence, the word "day" represents a noun.
