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").

Ex Input:
If something is in an ecosystem, it could be (A) invisible (B) vacuum of space (C) lacking life (D) alien

Ex Output:
C


Ex Input:
The way that the earth rotates and moves through space can effect how (A) the stars are viewed in the sky (B) how the moon phases (C) the heat of the sun (D) the plants we are able to eat

Ex Output:
A


Ex Input:
Magnetism (A) requires full contact between objects (B) requires objects to touch (C) can act only on contact (D) can act without contact between objects

Ex Output:

D