Electrostatics: JEE Main 2021 Physics question

A parallel plate capacitor with plate area 'A' and distance of separation 'd' is filled with a dielectric. What is the capacity of the capacitor when permittivity of the dielectric varies as : $\varepsilon (x) = {\varepsilon _0} + kx$, for $\left( {0 < x \le {d \over 2}} \right)$ $\varepsilon (x) = {\varepsilon _0} + k(d - x)$, for $\left( {{d \over 2} \le x \le d} \right)$