Find the mutual inductance in the arrangement, when a small circular loop of wire of radius $$R$$ is placed inside a large square loop of wire of side $$L(L \gg R)$$. The loops are coplanar and their centres coincide: 

A

$$M = \frac{\sqrt{2}\mu_0 R^2}{L}$$

B

$$M = \frac{2\sqrt{2}\mu_0 R}{L^2}$$

C

$$M = \frac{2\sqrt{2}\mu_0 R^2}{L}$$

D

$$M = \frac{\sqrt{2}\mu_0 R}{L^2}$$