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:
Which of the following properties best describes a material's ability to resist scratching?  
 (A) weight (B) flexibility (C) length (D) hardness

Ex Output:
D


Ex Input:
Which two protein molecules are essential for muscle contraction and relaxation?  
 (A) actin and myosin (B) collagen and tubulin (C) hemoglobin and myoglobin (D) amylase and polymerase

Ex Output:
A


Ex Input:
What advantage is gained by using radio telescopes as opposed to optical telescopes?  
 (A) viewed images are clearer (B) operation is less complex (C) ability to see through clouds and dust (D) ability to take up less space

Ex Output:

C