Sound waves traveled slowly down the canyon. Sound waves were absorbed by the canyon wall. Sound waves reflected off the canyon wall. Sound waves were refracted around the canyon.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Campers shouted toward a canyon wall. What characteristic of sound best explains why the campers heard an echo?
Possibilities:
- Sound waves traveled slowly down the canyon.
- Sound waves were absorbed by the canyon wall.
- Sound waves reflected off the canyon wall.
- Sound waves were refracted around the canyon.

Sound waves reflected off the canyon wall.