In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").
Q: What is an example of the Earth rotating on its axis? (A) constellations are only visible in some parts of the world during certain months (B) cloud coverage varies depending on the season (C) it is always cold in Antarctica (D) the equator moves up and down around the Earth
A:
A