The reason of current flow in PN junction in forward bias is :
Answer & explanation
Correct answer: option 3
An electric current will flow in the forward-bias direction due to the majority of carriers' migration over the p-n junction, which is known as forwarding current.
During formation of p-n junction p-side has excess holes and n-side has excess electrons. Hence, current tends to flow due to diffusion from p-side to n-side. This does not happen without an external bias because of the potential barrier at the junction.
When p-side is given a potential higher than the n-side, it aids in the flow of this diffusion current and hence, current flows.