Capcity of a spherical capacitor is `C_(1)` when in sphere is charged and outer sphere is earthed and when inner sphere is earthed and outer sphere charged. Then `(C_(1))/(C_(2))` is (a = radius of inner sphere b = radius of outer sphere)
A. 1
B. `(a)/(b)`
C. `(b)/(a)`
D. `(a+b)/(a-b)`