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]: the presence of which of these is required for the formation of cavernous chambers? (A) some carbonated soda (B) some carbon dioxide (C) some carbonic acid (D) carbon monoxide gas
[A]: C


[Q]: A rabbit might die if (A) it has insufficient money to buy food (B) all the greenery was burned in a fire (C) all of the rabbit's prey has disappeared (D) all the other rabbits shun it
[A]: B


[Q]: What lives in some zoo exhibits? (A) animal statues (B) felines (C) extinct species (D) people
[A]:
B