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:
There is a river at the base of Mount Tom. In the spring the water level is usually very high. In the summer it is lower. The higher level of water during the spring comes from  
 (A) hurricanes. (B) melting snow. (C) tornadoes. (D) evaporating water.

Ex Output:
B


Ex Input:
Which energy source is nonrenewable?  
 (A) sunlight (B) biomass (C) wind (D) fossil fuel

Ex Output:
D


Ex Input:
Which are two parts of the carbon cycle?  
 (A) freezing and thawing (B) growth and reproduction (C) evaporation and precipitation (D) photosynthesis and respiration

Ex Output:

D