In a series L-C circuit at the resonant frequency the

The correct answer is A. Current is maximum.

At the resonant frequency, the inductive reactance and capacitive reactance are equal and opposite, so they cancel each other out. This leaves only the resistance in the circuit, which is much smaller than the inductive and capacitive reactances. As a result, the current is much larger at the resonant frequency than it is at any other frequency.

Option B is incorrect because the current is maximum at the resonant frequency.

Option C is incorrect because the impedance is minimum at the resonant frequency.

Option D is incorrect because the voltage across C is maximum at the resonant frequency.