The correct answer is B: Amplitude at different times. A signal described in the time domain shows amplitude at different times. The time domain representation plots signal amplitude (voltage, current, or power) versus time. Time domain analysis shows how a signal changes over time - you see the waveform shape, amplitude variations, timing, and transient behavior. This is the most intuitive way to view signals - like looking at an oscilloscope display. The time domain is complementary to the frequency domain (which shows amplitude at different frequencies). Both representations contain the same information, just viewed from different perspectives. Time domain is useful for understanding signal timing, pulse shapes, and transient behavior.