The correct answer is: C. Both voltage and current amplification.
In series resonance, the impedance of the circuit is minimum and is equal to the resistance of the circuit. This means that the voltage across the inductor and capacitor is equal to the applied voltage. The current through the circuit is also maximum, since the impedance is minimum. Therefore, both voltage and current amplification occur in series resonance.
Option A is incorrect because voltage amplification does not occur in series resonance. The voltage across the inductor and capacitor is equal to the applied voltage, so there is no amplification of the voltage.
Option B is incorrect because current amplification does not occur in series resonance. The current through the circuit is maximum, but this is not due to amplification. The current is maximum because the impedance is minimum.
Option D is incorrect because both voltage and current amplification occur in series resonance.