c
Electric field inside parallel plate capacitor having charge $Q$ at place where dielectric is absent $=\frac{Q}{A\varepsilon_0}$
where dielectric is present $=\frac{Q}{A\varepsilon_0}$
As $K_1 < K_2\, so\, E_1 > E_2$
Hence graph $(c)$ correctly depicts the variation of electric field $E$ with distance $d.$