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.

Campers shouted toward a canyon wall. What characteristic of sound best explains why the campers heard an echo?  
 (A) Sound waves traveled slowly down the canyon. (B) Sound waves were absorbed by the canyon wall. (C) Sound waves reflected off the canyon wall. (D) Sound waves were refracted around the canyon.
C

Which method is the best safety procedure when working around open flames?  
 (A) wear an acid-resistant apron (B) wash your hands (C) tie back long hair (D) use an electric fan to blow gases from the flame
C

As Earth revolves around the Sun, the number of daylight hours varies from place to place. In which location would the number of daylight hours remain constant?  
 (A) North Pole (B) Prime Meridian (C) Equator (D) Antarctica

C