The output of the given circuit in Figure

When positive cycle is at A, diode will be in forward bias and resistance due to diode is approximately zero so potential across diode will be about zero. Similarly, when there is negative half cycle at A, diode will be in reverse bias and resistance will be maximum so potential difference across diode is V_m sin⁡ωt with negative at A. So we get only negative output at A, so it behaves like a half-wave rectifier with negative cycle at A in output, verifies the answer (3).