Four charges `+q, -1, +q` and `-q` are placed in order on the four consecutive corners of a square of side a. The work done in interchanging the positions of any two neighbouring charges of the opposite sign is

Options

A. `(q^(2))/(4 pi epsilon_(0) L) ( - 4 + sqrt(2))`
B. `(q^(2))/(4 pi epsilon_(0) L) ( 4 + 2sqrt(2))`
C. `(q^(2))/(4 pi epsilon_(0) L) ( 4 - 2sqrt(2))`
D. `(q^(2))/(4 pi epsilon_(0) L) ( 4 + sqrt(2))`

Answer

C