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 Q]: Soil could be Earth's what? (A) dermis (B) Buddy (C) Magic (D) Tears
[EX A]: A

[EX Q]: the mantle is (A) a level of our planet (B) the planet closest to ours (C) a kind of rock found on Earth (D) the deepest part of our planet
[EX A]: A

[EX Q]: In the desert, the cactus is a rare source of (A) food (B) shelter (C) moisture (D) shade
[EX A]:
C