A point charge q is placed inside a conducting spherical shell of inner radius 2R and outer radius 3R at a distance of R fro the centre of the shell. The electric potential at the centre of shell will (potential at infinity is zero).
A. `(q)/(2R)`
B. `(4q)/(3R)`
C. `(5q)/(6R)`
D. `(2q)/(3R)`