A small square loop of wire of side \[\ell \] is placed inside a large square loop of wire of side \[L(L>\ell )\].The loop are coplanar and their centre coincide. The mutual inductance of the system is proportional to

• A. \[\ell /L\]
• B. \[{{\ell }^{2}}/L\]
• C. \[L/\ell \]
• D. \[{{L}^{2}}/\ell \]