Which one of the following statements regarding ac circuits is correct? A. Current and voltage are in phase through an inductor B. Current leads the voltage through an inductor C. Current lags the voltage through an inductor D. All of the above E. None of the above

The correct answer is: C. Current lags the voltage through an inductor.

In an inductor, current lags the voltage by 90 degrees. This is because the inductor stores energy in a magnetic field, and the current must build up this magnetic field before it can flow through the inductor. The amount of lag is proportional to the inductance of the inductor.

Option A is incorrect because current and voltage are not in phase through an inductor. Option B is incorrect because current lags the voltage through an inductor, not leads it. Option D is incorrect because only one of the statements is correct. Option E is incorrect because at least one of the statements is correct.