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.

Example Input: Which would provide evidence of seafloor spreading?  
 (A) higher levels of salinity in the ocean water (B) stronger currents at the surface of the ocean (C) cooled magma found on the edge of the plates (D) greater reproduction levels for organisms at the bottom of the ocean
Example Output: C

Example Input: A scientific guess about the cause and effect of an event is called  
 (A) a variable. (B) a theory. (C) a hypothesis. (D) an observation.
Example Output: C

Example Input: Which human body system produces the hormones that regulate growth?  
 (A) skeletal (B) digestive (C) circulatory (D) endocrine
Example Output:
D