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: The Grand Canyon is an example of  
 (A) erosion. (B) deposition. (C) an earthquake. (D) volcanic activity.

Answer: A


Question: Which of these technologies helps a power company use renewable energy for the production of electricity?  
 (A) hydroelectric power (B) nuclear power plants (C) natural gas generators (D) coal-fired power plants

Answer: A


Question: In the life cycle of a fly, which stage comes after the larval stage?  
 (A) egg (B) adult (C) nymph (D) pupa

Answer:
D