You will be given a definition of a task first, then some input of the task.
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").

The gravitational pull of the sun causes what phenomenon? (A) planetary revolution (B) creation of moons (C) creation of rings (D) planetary cooling
Output:
A