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: if a chemical reaction occurs, it might have been triggered by which of these? (A) a person yelling at it (B) a person walking by it (C) a person looking at it intently (D) a person cranking up the room heater
Example Output: D

Example Input: Once the grounds frost over and the air grows chilled (A) beaches are opened (B) humans go naked (C) birds lay eggs (D) roses die
Example Output: D

Example Input: what can be found where photosynthesis takes place? (A) some green pigmentation (B) some blue pigment (C) some chlorine pigment (D) some chloride
Example Output:
A