An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current `I` along the same direction is shown in figure. Magnitude of force per unit length on the middle wire `'B'` is given by

Options

A. `(mu_0i^2)/(2pid)`
B. `(2mu_0i^2)/(pid)`
C. `(sqrt2mu_0i^2)/(pid)`
D. `(mu_0i^2)/sqrt(2pid)`

Answer

D