You are given a science question (hard-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]: Which of these reduces the need for people to use nonrenewable resources?  
 (A) recycling paper products (B) watering the lawn once a week (C) designing cars that are fuel efficient (D) using coal to generate electricity
[EX A]: C

[EX Q]: An astronomer observes that a planet rotates faster after a meteorite impact. Which is the most likely effect of this increase in rotation?  
 (A) Planetary density will decrease. (B) Planetary years will become longer. (C) Planetary days will become shorter. (D) Planetary gravity will become stronger.
[EX A]: C

[EX Q]: It takes approximately 365 days for  
 (A) the Sun to orbit around Earth. (B) the Moon to orbit around Earth. (C) Earth to orbit around the Sun. (D) Earth to orbit around the Moon.
[EX A]:
C