Answer:
B. An echo
Step-by-step explanation:
An echo is the sound heard after the reflection of sound waves from a hard surface. It has both advantages and disadvantages with respect to its applications.
Some of it applications include;
i. it can be used to determine the depth of the sea
ii. it can be used in crude oil exploration
iii. it can be used to determine the speed of sound in air
An echo is different to reverberation of sound.