Answer:
According to this dictionary definition, the sentence that uses the word cacophonous correctly is D) The substitute teacher had no idea that the fifth grade band class would make such cacophonous music.
Step-by-step explanation:
Cacophonous is an adjective used to describe a harsh or discordant mixture of sounds. Within this list, the only sentence that makes reference to sounds is sentence D, apart from the fact that it makes perfect sense with the context provided in the sentence.