A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P a distance `R/2` from the centre of the shell is
A. `((q+Q))/(4piepsilon_(0))(2)/(R)`
B. `(2Q)/(4piepsilon_(0)R)`
C. `(2Q)/(4pi epsilon_(0)R)-(2q)/(4pi epsilon_(0)R)`
D. `(2Q)/(4pi epsilon_(0)R)+(q)/(4pi epsilon_(0)R)`
