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 these will best separate a saltwater solution?  
 (A) using a paper filtering system (B) using chromatography (C) allowing the salt to settle (D) allowing the water to evaporate

Ex Output:
D


Ex Input:
Which property of proteins best allows them to perform an enormously diverse range of functions?  
 (A) their large, chemical-energy reserve (B) their large, stored-electric potential (C) the complexity of their folded structure (D) the wide variety of elements they include

Ex Output:
C


Ex Input:
After rubbing a rubber brush on wool, Gilbert is able to use the brush to pick up small strips of paper. What causes the paper to be attracted to the brush?  
 (A) gravity (B) electric current (C) static electricity (D) magnetism

Ex Output:

C