A wire in the shape of a square frame carries a current I and produces a magnetic field $$B_s$$ at its centre. Now the wire is bent in the shape of a circle and carries the same current. If $$B_c$$ is the magnetic field produced at the centre of the circular coil, then $$\frac{B_s}{B_c}$$ is

A

$$8\pi^2$$

B

$$\frac{8\pi^2}{\sqrt{2}}$$

C

$$\frac{8\sqrt{2}}{\pi^2}$$

D

$$8\pi\sqrt{2}$$