The concept of displacement current was proposed by:

The concept of displacement current was proposed by Maxwell

CONCEPT:

Displacement current (ID): 

• It is that current that comes into existence, in addition to the conduction current, whenever the electric field and hence the electric flux changes with time
• To modify Ampere’s law, Maxwell followed a symmetry consideration.
• By Faraday’s law, a changing magnetic field induces an electric field, hence a changing electric field must induce a magnetic field.
• As currents are the usual sources of the magnetic field, a changing electric field must be associated with the current.
• Maxwell called that current as displacement current.
• To maintain the dimensional consistency, the displacement current is added in ampere’s law: 

\(\Rightarrow\oint \vec B \cdot \overrightarrow {dl} = {\mu _0}I + {\mu _0}{\epsilon_0}\left( {\frac{{d{{\rm{\Phi }}_E}}}{{dt}}} \right)\)

Where, \({\epsilon_0}\left( {\frac{{d{{\bf{\Phi }}_E}}}{{dt}}} \right)\) is the displacement current.

EXPLANATION:

• From the above, it is clear that the concept of displacement current was proposed by Maxwell. Therefore option 4 is correct.