Displacement current exists only when

The correct answer is Option (1) → electric field is changing

Maxwell’s displacement current is defined through the rate of change of electric flux, \( i_d = \varepsilon_0\,\displaystyle\frac{d\Phi_E}{dt} \). It is non-zero only when the electric flux, and hence the electric field, changes with time; if the field is steady, \( d\Phi_E/dt = 0 \) and there is no displacement current.

A changing magnetic field gives rise to an induced emf (Faraday’s law), not to a displacement current, so Options (2) and (4) do not decide its existence, and Option (3) is the opposite of the condition.

NCERT (2026-27):
Displacement Current – “… The source of a magnetic field is not just the conduction electric current due to flowing charges, but also the time rate of change of electric field. More precisely, the total current i is the sum of the conduction current denoted by i_c, and the displacement current denoted by i_d (= ε₀ (dΦ_E/dt)).”