A parallel-plate capacitor is made using two circular plates of radius a, with the bottom plate on the xy plane, centered at the origin. The top plate is located at z = d, with its center on the z axis. Potential V₀ is on the top plate; the bottom plate is grounded. Dielectric having radially dependent permittivity fills the region between plates. The permittivity is given by ∈(ρ) = ∈₀(1 + ρ²/a²). Find

(a) E;

(b) D;

(c) Q;

(d) C.