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 of the following units best represents the density of an object?  
 (A) kg (B) hr (C) m/s^2 (D) g/cm^3

SOLUTION: D

PROBLEM: What kind of energy conversion occurs after a candle is lit?  
 (A) friction to electrical energy (B) light energy to heat energy (C) mass to kinetic energy (D) chemical energy to light energy

SOLUTION: D

PROBLEM: A mother hen clucks loudly when danger is near and her chicks quickly gather around her. Which sense helps the chicks receive this warning about danger from their mother?  
 (A) smell (B) taste (C) sight (D) sound

SOLUTION:
D