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:
A girl signals her friend by shining a flashlight on a mirror. Her friend can see the signal because  
 (A) heat energy can be transferred from one object to another (B) mechanical energy can be transferred from one object to another (C) sound energy can be reflected from one object to another (D) light energy can be reflected from one object to another

Ex Output:
D


Ex Input:
The transfer of heat in the atmosphere by winds that circulate between the equator and the poles is an example of  
 (A) radiation. (B) insulation. (C) convection. (D) conduction.

Ex Output:
C


Ex Input:
What is a common use of the mineral graphite?  
 (A) to make glass (B) as a source of iron (C) to make pencil leads (D) as a household cleaner

Ex Output:

C