The current density varies with radial distance 'r' as `j= a r^(2)` in a cylindrical wire of radius R. The current passing through the wire between radial distance `(R )/(3) and (R )/(2)` is

Options

A. `(65pi aR^(4))/(2592)`
B. `(25pi a R^(4))/(72)`
C. `(65pi a^(2)R^(3))/(2938)`
D. `(81pi a^(2)R^(4))/(144)`