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 Q]: What form of energy is being used when a person pushes a wooden block across the floor?  
 (A) mechanical (B) magnetic (C) sound (D) electrical
[EX A]: A

[EX Q]: 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 A]: D

[EX Q]: The first stage of soil formation is the weathering of rock into fine particles. To make a good soil for growing plants, which would be best to add to the rock particles?  
 (A) minerals (B) sand (C) organic matter (D) silt
[EX A]:
C