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]: Sleet is made out of water that is (A) vapor (B) hot (C) liquid (D) cold
[EX A]: D

[EX Q]: When the old man was much younger, he still had (A) brown eyes (B) baldness (C) gray hair (D) wrinkled skin
[EX A]: A

[EX Q]: Which pollutant is most likely caused by humans activity? (A) bricks (B) bovine farts (C) rocks (D) oxygen
[EX A]:
B