TASK DEFINITION: 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.
PROBLEM: Which material best conducts heat and electricity?  
 (A) metal (B) plastic (C) rubber (D) wood

SOLUTION: A

PROBLEM: When a hammer strikes a nail, the nail  
 (A) exerts balanced forces that helps it from moving. (B) exerts a force equal to the weight of the hammer. (C) exerts an unbalanced force that changes its velocity. (D) exerts an equal and opposite force back on the hammer.

SOLUTION: D

PROBLEM: Vinegar and water are placed in a container and stirred. What is formed when they are mixed?  
 (A) gas (B) solid (C) solution (D) compound

SOLUTION:
C