Two long parallel wires P and Q are held perpendicular to the plane of the paper with distance of 5m between them. If P and Q carry current of 2.5 A and 5A respectively in the same direction, then the magnetic field at a point halfway between the wires is

Options

A. `mu_0//pi`
B. `sqrt3 mu_0 // pi`
C. `mu_0//2 pi`
D. `3 mu_0//2 pi`.