The concentric, thin metallic spheres of radii `r_(1)` and `r_(2) (r_(1) gt r_(2))` carry charges `q_(1)` and `q_(2)` respectively. Then the electric potential at distance `r (r_(2) lt r lt r_(1))` will be `(1)/(4pi epsilon_(0))` times
A. `k((Q_(1) + Q_(2))/(r ))`
B. `k((Q_(1))/(r ) + (Q_(2))/(R_(2)))`
C. `k((Q_(2))/(r ) + (Q_(1))/(r ))`
D. `k((Q_(1))/(R_(1)) + (Q_(2))/(r ))`