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").

Example Input: Which of the following items can perform photosynthesis? (A) a flying wasp (B) a speedy cheetah (C) wet dirt (D) a yellow tulip
Example Output: D

Example Input: A way for an octopus to evade predators is to (A) befriend the predator (B) emulate a rock (C) swim around (D) bury itself underground
Example Output: B

Example Input: Chemical changes can occur when (A) plastic is used for eating utensils (B) oxygen circulates in a vacuum chamber (C) H2O is exposed to air (D) Na is added to Cl
Example Output:
D