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:
Which two body systems maintain the level of glucose in the blood?  
 (A) nervous and respiratory systems (B) digestive and endocrine systems (C) muscular and immune systems (D) skeletal and cardiac systems

Ex Output:
B


Ex Input:
Which of these will most likely harm a habitat?  
 (A) planting trees (B) water pollution (C) rainfall (D) sunlight

Ex Output:
B


Ex Input:
In the rock cycle, sedimentary rock forms when rock is  
 (A) crystallized into natural glass. (B) exposed to great temperature. (C) melted into liquid magma. (D) broken down by weathering.

Ex Output:

D


