Explanation: Sensitivity refers to a receiver's ability to detect weak signals, determined by its front-end design, noise figure, and internal noise characteristics. It's a measure of how low a signal power level can be detected and still produce a usable output. The volume control, however, adjusts the amplitude of the *audio output* of the receiver. It amplifies or attenuates the audio signal *after* it has been processed and demodulated by the receiver's RF, IF, and detector stages. Turning up the volume makes an already-received signal louder, but it doesn't change the receiver's fundamental ability to "hear" or process a faint radio wave entering its antenna. Therefore, adjusting the volume control has no effect on the receiver's sensitivity (C). Options A and D incorrectly conflate audio output level with the receiver's inherent detection capability. Option B describes the function of a squelch control, which sets a threshold to mute audio noise when no signal is present, not a volume control.