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 Q]: Organisms contribute to the water cycle mainly through the process of  
 (A) irrigation. (B) evaporation. (C) precipitation. (D) transpiration.
[EX A]: D

[EX Q]: Use of nuclear fuel would most likely reduce human contributions to which environmental problem?  
 (A) ozone thinning (B) landfill creation (C) shoreline erosion (D) greenhouse heating
[EX A]: D

[EX Q]: High average daily temperature and heavy annual precipitation are found in a  
 (A) desert. (B) grassland. (C) rainforest. (D) tundra.
[EX A]:
C