Which component primarily varies its resistance based on sound intensity in microphones?

In microphones, the component that primarily varies its resistance based on sound intensity is the variable resistor, commonly referred to as a potentiometer in this context. As sound waves hit the diaphragm of the microphone, they induce mechanical vibrations. These vibrations create changes in the electrical resistance that the microphone senses and converts into an audio signal.

Variable resistors can adjust their resistance level in response to the amplitude of the incoming sound waves. This behavior is crucial for capturing varying sound intensities and translating them into electrical signals. Other components, like variable inductors and capacitors, do not directly respond to sound intensity in the same way. Meanwhile, fixed resistors maintain a constant resistance and do not change with sound levels. This is why the variable resistor is the correct answer when discussing components that respond to sound intensity in microphones.