If the voltage and the current developed in an AC circuit reach their peak values at the same time (with a phase angle difference of zero), what is the power factor considered to be?

Correct Answer: Option D — unity (1.0)

When voltage and current waveforms reach their peaks simultaneously, the phase angle difference is zero degrees. The cosine of zero is 1.0, representing a purely resistive load where real power equals apparent power at unity power factor.