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]: The circulatory system is so long it (A) could be wrapped around the earth (B) is the length of a horse (C) is the length of the universe (D) is the length of the universe
[EX A]: A

[EX Q]: What is a source of oxygen through photosynthesis? (A) lakes (B) car engines (C) sunflowers (D) people
[EX A]: C

[EX Q]: chlorophyll (A) would avoid being pinched on St. Patrick's day (B) would blend in well in the arctic (C) is the color of an embarrassed person's cheeks (D) is a color used also to describe someone sad
[EX A]:
A