Sonar uses sound waves to measure the distance between objects underwater. It can do this by transmitting and detecting sound waves. What behavior of sound waves explains how sonar is used A. refraction
B. reflection
C. diffraction​

reflection

Explanation:

this is because when you send out the sound waves into the water, it will come back to the detector, right?

but how?

this is because sound waves can be reflected off a hard and flat surface which in this case is a sea bed. it reflects off the sea bed by obeying the laws of reflection ( angle of incidence equals to the angle of reflection)

hope you get it, if not please report it so that someone else gets to try it

where's the following? you gotta add it to know what the choices are

explanation: