Two non-conducting solid spheres of radii R and 2R, having uniform volume charge densities p1 and p2 respectively, touch each other. The net electric field at a distance 2R from the centre of the smaller sphere, along the line joining the centre of the spheres is zero. The ratio p1/p2 can be
(A) -4
(B) - 32/25
(C) 32/25
(D) 4