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: Diseases that can be transmitted between organisms are  
 (A) infectious. (B) inherited. (C) environmental. (D) congenital.
Example Output: A

Example Input: Some birds fly south in the fall and return in the spring. This is an example of  
 (A) migration (B) camouflage (C) hibernation (D) growth
Example Output: A

Example Input: What activity must mRNA do in traveling from DNA to protein synthesis sites in eukaryotic cells that does not occur in prokaryotic cells?  
 (A) duplicate itself (B) break off some of its phosphates to release energy (C) cross a membrane (D) coil into a compact crystal form
Example Output:
C