Function of Imagery: Short Fiction Practice Test

In a short story, a man attends his first AA meeting and sits in a folding chair near the exit. People speak calmly, but he keeps rubbing the ridges of his coffee cup lid. The narrator describes his craving as "a radio turned low, still insisting on its song". Which choice best explains the function of the bolded imagery?

In a short story, a boy helps his aunt clean a restaurant kitchen after closing. The floor is slick, and the mop water turns gray. The narrator describes the grease on the tiles as "a stubborn sheen, like laughter that won’t admit it’s tired". Which choice best explains how the bolded imagery functions in the passage?