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:
Human DNA includes a class of genes called "tumor suppressors." What do these genes do in bone cells?   
 (A) They restrict cell cycle progression in bone cells. (B) They promote the rapid development of bone cells. (C) They limit the number of bones in the human body. (D) They enable phosphorus and calcium to enter bone cells.

Ex Output:
A


Ex Input:
One important use of coal is to produce energy for homes. Coal can be burned and converted to  
 (A) wind energy. (B) nuclear energy. (C) electrical energy. (D) solar energy.

Ex Output:
C


Ex Input:
Lions tend to prey on primary consumers like zebras and gazelles. If there were a sudden decline in a population of lions, which ecological imbalance would most likely occur in the habitat?  
 (A) overgrazing (B) eutrophication (C) invasion by non-native species (D) overproduction of greenhouse gases

Ex Output:

A