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

Answer: D


Question: What happens to the water vapor in an air mass as it ascends?  
 (A) It freezes. (B) It condenses. (C) It vaporizes. (D) It polarizes.

Answer: B


Question: What allows a light bulb to give off light?  
 (A) the current flowing through the wire to the light bulb (B) the light bulb giving electrical energy to the battery (C) the light bulb generating heat energy (D) the battery pushing light through the wire

Answer:
A