Answer:
D. It points out that evenings are quiet.
Step-by-step explanation:
According to the given lines from "A Cave of Angelfish Huddle Against the Moon", which says "Put an ear to the light at fall of dark and you will hear nothing", the best explanation of this imagery is that it points out that evenings are quiet.
This is because, from the quote, the narrator says that when you put an ear to light at the fall of dark, you won't hear anything.