You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Ex Input:
The energy that is stored in food originally comes from  
 (A) air (B) soil (C) sunlight (D) water

Ex Output:
C


Ex Input:
Which characteristic of sound makes it possible for bats to fly in the dark without hitting any objects?  
 (A) refraction (B) reflection (C) conduction (D) amplification

Ex Output:
B


Ex Input:
What characteristic of carbon [C] makes it essential to living organisms?  
 (A) Carbon forms crystal structures under certain conditions. (B) Carbon can exist as a solid, liquid, or gas. (C) Carbon bonds in many ways with itself to form chains. (D) Carbon exists in radioactive forms.

Ex Output:

C