Two similar coils of radius R are lying concentrically with their planes at angles to each other. The currents flowing in them are I and 2l respectively. The resultant magnetic field induction at the centre will be :

• A

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{2\mathrm{R}}$

• B

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{\mathrm{R}}$

• C

  $\frac{\sqrt{5}{\mathrm{\mu }}_0\mathrm{I}}{2\mathrm{R}}$

• D

  $\frac{3{\mathrm{\mu }}_0\mathrm{I}}{2\mathrm{R}}$