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 light is refracted when (A) it shines at a gem (B) it shines at a mirror (C) it reflects off a spoon (D) it reflects off a car

Ex Output:
A

Ex Input:
An electron microscope can (A) move small magnets around (B) create completed replicas of animals (C) burn plastic with ease (D) recreate an entire image

Ex Output:
D

Ex Input:
Freezing point refers to: (A) the temperature below which gas turns to liquid (B) the temperature above which liquid stops being liquid (C) the temperature below which solid turns to liquid (D) the temperature below which liquid stops being liquid

Ex Output:
D