Answer:
capacitors only
Explanation:
When a battery or a DC supply is used to drive a circuit, the current becomes zero after some time. But when an AC generator is used in the same circuit, the current is non-zero and is alternates.
Here, a combination of capacitors are used to drive the circuit.
As we know in capacitor,
current, i = c. dv/dt
where c is capacitance, v is voltage and t is time.
So as in DC voltage, v (voltage) is constant and hence current i = 0.
But in AC voltage, the voltage v varies with time t. Therefore here capacitors are used only.
Capacitors are used to store energy.
Thus the answer is capacitors.