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.

Input: Consider Input: Sir Isaac Newton stated that every object in the universe attracts matter. The attraction depends on the mass of an object and the distance between the objects. What type of force did Newton describe?  
 (A) centripetal force (B) generalized force (C) centrifugal force (D) gravitational force

Output: D


Input: Consider Input: Which substance do all living things require to survive?  
 (A) blood (B) water (C) carbon dioxide (D) organic soil

Output: B


Input: Consider Input: To observe materials up close and in greater detail we use  
 (A) gripping tools. (B) optical tools. (C) cutting tools. (D) polishing tools.


Output: B