Two wire loops PQRSP formed by joining two semicircular wires of radii -R₁, and R₂, carries a current as shown in fig. The magnitude of the magnetic 

induction at the centre C is

• A

  $\frac{{\mathrm{\mu }}_0\mathrm{i}}{4}\left[\frac{1}{{\mathrm{R}}_1}-\frac{1}{{\mathrm{R}}_2}\right]$

• B

  $\frac{{\mathrm{\mu }}_0\mathrm{i}}{2}\left[\frac{1}{{\mathrm{R}}_1}-\frac{1}{{\mathrm{R}}_2}\right]$

• C

  $\frac{{\mathrm{\mu }}_0\mathrm{i}}{4}\left[\frac{1}{{\mathrm{R}}_1}+\frac{1}{{\mathrm{R}}_2}\right]$

• D

  $\frac{{\mathrm{\mu }}_0\mathrm{i}}{2}\left[\frac{1}{{\mathrm{R}}_1}+\frac{1}{{\mathrm{R}}_2}\right]$