Two non-conducting spheres of radii $$R_1$$ and $$R_2$$ and carrying uniform volume charge densities $$\rho$$ and $$\rho$$ respectively, are placed such that they partially overlap, as shown in the figure. At all points in the overlapping region,

A

the electrostatic field is zero.

B

the electrostatic potential is constant.

C

the electrostatic field is constant in magnitude.

D

the electrostatic field has same direction.