Correct Answer: Candela

Solution : The correct option is Candela.

The term candela is not associated with sound waves. Instead, it is a luminous intensity measuring unit that is largely employed in optics, and lighting. In contrast, the decibel is related to sound and quantifies sound intensity or loudness; hertz measures the frequency or pitch of sound waves; and Mach is a unit used to describe the speed of objects in a medium relative to the speed of sound, particularly in the context of supersonic, and subsonic velocities in aviation, and fluid dynamics.