Correct Option (d)
Explanation:
During - ve cycle, diode will not allow the signal to
For Vi < 0, the diode is reverse biased and hence offer infinite resistance, so circuit would be like as shown in Fig (ii) and Vo = 0
For Vi >0, the diode is forward biased and circuit would be as shown in Fig. (iii) and Vo = Vi.
Hence, the option (d) is correct.