Answer:
C) Adverb
Explanation:
The phrase is
Shelly's beautiful dance thoroughly captivated the audience.
The verbs used are To Be, to captivate, and To Dance
The adjective used is beautiful
The Nouns are "Shelly", "Dance", and "The audience"
Which leaves us with thoroughly, which is being used to add meaning to qualify "captivated", making it an adverb.
By definition, an adverb is: "a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, degree, etc"
