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: A cut to the skin is treated with antiseptic first to avoid  
 (A) an immune response. (B) a bacterial infection. (C) bruising of tissues. (D) an allergic reaction.
Example Output: B

Example Input: Some scientists believe that the mass extinction of dinosaurs was caused by the impact of a large meteorite on Earth. This impact would have caused a darkening of the sky due to dust blown into the upper atmosphere. This darkening would have reduced the sizes of some ecosystems because of  
 (A) longer seasons. (B) accelerated erosion. (C) reduced photosynthesis. (D) increased number of hurricanes.
Example Output: C

Example Input: What is the relationship between mass and gravitational pull?  
 (A) Lower gravitational pull creates more mass. (B) Higher gravitational pull creates more mass. (C) Lower mass creates higher gravitational pull. (D) Higher mass creates higher gravitational pull.
Example Output:
D