The correct answer is A. Square wave.
The peak factor is the ratio of the peak value of a waveform to its rms value. A square wave has a peak factor of 1.414, while a sine wave has a peak factor of 1. A half wave rectified sine wave has a peak factor of 1.111, and a triangular wave has a peak factor of 1.732.
A square wave is a periodic waveform with a constant amplitude and a period that is twice the time it takes for the wave to go from one extreme to the other. The sine wave is a periodic waveform with a constant amplitude and a period that is equal to the time it takes for the wave to go from one extreme to the other. The half wave rectified sine wave is a periodic waveform that is created by taking the positive half cycles of a sine wave and discarding the negative half cycles. The triangular wave is a periodic waveform with a constant slope and a period that is equal to the time it takes for the wave to go from one extreme to the other.
The peak factor of a waveform is a measure of how sharp the peaks of the waveform are. A waveform with a higher peak factor has sharper peaks than a waveform with a lower peak factor. The peak factor of a waveform is important in many applications, such as power electronics and telecommunications.