The correct answer is -
bats and dolphins.
Echolocation (also termed as biological sonar) can be described as the ability of some animals to detect objects present in their environment by sensing echoes and sound waves of those objects.
Dolphin use echolocation to see various organisms/objects better underwater.
Bats loctate their food during dark by sending sound waves, which hit a food source/an object and bounces back, producing echo that is ultimately sensed by bats.