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 Input:
A learned behavior is exhibited when (A) squinting in bright light (B) nailing up a picture frame (C) blinking and gulping air (D) inhaling and exhaling during sleep

Ex Output:
B

Ex Input:
A tone is made when a hammer makes contact with (A) a waterfall (B) air (C) an solid object (D) a log

Ex Output:
C

Ex Input:
When there is an increase in atmospheric temperature, then (A) glaciers become too large (B) global sea level decreases (C) Antartica and Greenland icebergs will melt (D) Earth absorbs less sunlight

Ex Output:
C