The correct answer is sound. Sonar uses sound waves to detect objects underwater. Sound waves are emitted from a sonar device and travel through the water. Whenever these sound waves encounter an object, such as a submarine or a fish, they bounce back to the sonar device. By measuring the time it takes for the sound waves to return, the distance to the object can be calculated. This is how sonar is able to detect objects in the water.
The type of wave used in sonar to detect objects is sound.
