The output of the given circuit in figure given below,

           

1. would be zero at all times.
2. would be like a half wave rectifier with positive cycles in output.
3. would be like a half wave rectifier with negative cycles in output.
4. would be like that of a full wave rectifier.
(c) Hint: The output depends on the biasing of the diode.
Step 1: Find the output for the first half cycle.
Due to forward biasing during the positive half cycle of input AC voltage, the resistance of p-n junction is low. The current in the circuit is maximum. In this situation, a maximum potential difference will appear across resistance connected in series of circuit. This result into zero output voltage across p-n junction.
Step 2: Find the output in the next half-cycle.
Due to reverse biasing during the negative half cycle of AC voltage, the p-n junction is reverse biased. The resistance of p-n junction becomes high which will be more than the resistance in series. That is why, there will be voltage across p-n junction with negative cycle in output.