Rectifiers & Filters question from JEE Main 2009 (AIEEE)

Answer: (b)

1. Single diode in series with $R$: it is a half-wave rectifier.
2. Current flows only during the half cycle that forward biases $D$, and is zero in the other half.
3. So $I$ shows one positive half-sine, then a gap of equal length, and so on. So the answer is (b).