Final Answer:
It accurately describes the phenomenon Cindy and her family experienced when noticing their voices echoing in certain places. Therefore the correct option is B. A reflected sound wave
Step-by-step explanation:
When Cindy and her family noticed their voices echoing in certain places, they were experiencing reflected sound waves. Sound waves travel in waves and when they encounter a surface, they can bounce back or reflect off it, causing an echo.
This phenomenon occurs when the sound waves encounter a hard surface and get reflected back towards the source of the sound. In Cindy's case, the sound waves produced by their voices hit certain surfaces, like walls or mountains, and bounced back to their ears, creating an echo.
Therefore the correct option is B. A reflected sound wave