Two identicaln thin rings each of radius 10 cm carrying charges 10 C and 5 C are coaxially placed at a distance 10 cm apart. The work done in moving a charge q from the centre of the first ring to that of the second is
A. `(q)/(8piepsilon_(0)).[(sqrt(2)+1)/(sqrt(2))]`
B. `(q)/(8piepsilon_(0)).[(sqrt(2)-1)/(sqrt(2))]`
C. `(q)/(4piepsilon_(0)).[(sqrt(2)+1)/(sqrt(2))]`
D. `(q)/(4piepsilon_(0)).[(sqrt(2)-1)/(sqrt(2))]`
