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: Using mirrors to focus collected light from heavenly bodies allows (A) detailed observation (B) foregone conclusions (C) radiation experiments (D) celestial music
Example Output: A

Example Input: Two females usually can produce (A) children (B) a progeny (C) offspring (D) nothing
Example Output: D

Example Input: How does ice wedging cause rocks to crack? (A) releasing gas (B) melting down (C) being cold (D) growth in openings
Example Output:
D