The forward biased diode

Hint: Here, we get the answer by knowing about the PN Junction diode and its characteristics of forward bias current flows from higher potential to lower potential and from opinion you can get the answer.

Complete step by step solution:
The P-N junction diode can be represented by

in which the ‘+’ side is called a cathode. In the forward bias current flows from anode to cathode and anode must be connected to higher potential and cathode must be connected to lower potential. When voltage is supplied from the battery source current starts to flow from higher potential to lower potential and is the same way diodes must be inserted that current enter from anode side and leave from cathode side. Anode side is also called P side and cathode side also called N side. Therefore the voltage must be higher at the anode side and voltage must be lower at the cathode side. So, from options we can see in option(D) only, the P side is at higher potential than n side.
P side (anode) at ’0’ volt and n side (cathode) at ‘-2’ volt.

Note: In the case of reverse bias, the polarity of battery change and there current enters to n side (cathode) and leaves from p side (anode). We can see option(C) n side at higher potential (5V) and p side at lower potential (3V). So, it is the case of reverse bias diode circuits.