You are given a science question (hard-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:
A lake has been used for more than a century to irrigate crops. How has this practice most likely affected this resource?  
 (A) It decreased the salt content of the water. (B) It increased the evaporation rate of the water. (C) It increased the number of fish in the lake. (D) It decreased the volume of the lake.

Ex Output:
D


Ex Input:
Which factor would most likely limit the number of mice living in an area?  
 (A) plentiful resources (B) stable climate (C) more predators (D) less competition

Ex Output:
C


Ex Input:
Louis Pasteur created a process that reduced the amount of bacteria in milk. How does this process most likely benefit people?  
 (A) by helping to prevent food allergies (B) by encouraging people to eat healthy foods (C) by helping to keep people from becoming ill (D) by curing diseases caused by lack of vitamins

Ex Output:

C