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: Different units of measurement are more useful in some settings than in others. Which unit of measurement is most used when comparing distances within the solar system?  
 (A) the mile (B) the kilometer (C) the light year (D) the astronomical unit
Example Output: D

Example Input: Which part of an atom is involved in chemical reactions?  
 (A) nucleus and its particles (B) negatively-charged particles (C) neutrally-charged particles (D) positively-charged particles
Example Output: B

Example Input: In 1989, the unusually low snowpack in portions of the Sierra Nevada Mountains led to a widespread emergence of Edith's checkerspot butterflies in April. In these regions, flowers do not appear until May. What was the most likely result of the early emergence of these butterflies?  
 (A) Most butterflies did not survive. (B) Most butterflies reproduced earlier. (C) Most butterflies switched to other food sources. (D) Most butterflies adapted to the new environment.
Example Output:
A