P-N Junction Diode question from MHT CET 2024 (11 May, Shift 1)

Answer: (d)

1. A p-n diode works as a rectifier, as a photodiode/solar cell (light to electrical energy) and as an LED (light emission).
2. It has no gain, so it cannot amplify a signal; amplification needs a transistor.
3. So the answer is (d) for increasing the amplitude of an a.c. signal.