You are given a science question (hard-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.

Input: Consider Input: The nucleus of the cell controls cell activity. Which body system performs a similar function in humans?  
 (A) circulatory system (B) central nervous system (C) skeletal system (D) integumentary system

Output: B


Input: Consider Input: Which of these activities is used to conserve water?  
 (A) planting crops that survive in droughts (B) running water while brushing teeth (C) washing vehicles frequently (D) watering grass after a rainfall

Output: A


Input: Consider Input: When considering if scientific research is correct, all of these are important except  
 (A) other support for the research study findings. (B) the way the research study was designed. (C) when the research study was done. (D) how the author feels about the research study.


Output: D