An ac source (sinusoidal source with frequency 50 Hz) is connected in series with a rectifying diode, a $$100\ \Omega$$ resistor, a $$1000\ \mu\text{F}$$ capacitor and a milliammeter. After some time the milliammeter reads zero. The voltage measured across the capacitor with a dc voltmeter is

A

the peak voltage of the ac source

B

rms voltage of the ac source

C

average voltage of the ac source over a half cycle

D

average voltage of the ac source over a full cycle