Which of the following statements is true?

Adverbs modify verbs, adjectives, or other adverbs and typically answer questions like how, when, where, or to what extent. However, "knew" does not modify any other word in the sentence; instead, it conveys the action of knowing, confirming its role as a verb, not as an adverb.

Adjectives modify nouns and pronouns, providing more detail about them. In this case, "really" modifies the degree of an adjective or another adverb, indicating its function as an intensifier rather than as an adjective itself. Thus, it cannot be accurately classified as an adjective.

Nouns represent people, places, things, or ideas. Since "really" does not serve as a subject or object in the sentence and instead modifies the intensity of another word, it cannot be classified as a noun. Its role as an intensifier or adverbial modifier is the correct classification.