The region between two concentric spheres of radii 'a' and 'b', respectively(see figure), has volume charge density `rho=A/r` , where A is a constant and r is the distance from the centre. At the centre of the spheres is a point charge Q. The value of A such that the electric field in the region between the spheres will be constant, is :

Options

A. `(2Q)/(pia^2)`
B. `Q/(2pia^2`
C. `Q/(2pi(b^2-a^2))`
D. `(2Q)/(pi(b^2-a^2))`

Answer

B