instruction:
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:
At a weightlifting competition, two competitors lifted the same weight to the same height. The second competitor accomplished the lift 2 seconds faster than the first competitor. This demonstrated that the second competitor had more  
 (A) energy than the first. (B) inertia than the first. (C) power than the first. (D) work than the first.
answer:
C


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:
Which alternative energy resource changes part of a river into a lake?  
 (A) solar energy (B) geothermal energy (C) hydropower (D) biofuel energy
answer:

C