The magnetic induction at point O due to the current carrying loop is

• A

  $\frac{3{\mathrm{\mu }}_{\mathrm{o}}\mathrm{i}}{4\mathrm{R}}$

• B

  $\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{i}}{2\mathrm{R}}$

• C

  $\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{i}}{6\mathrm{R}}$

• D

  $\frac{3{\mathrm{\mu }}_{\mathrm{o}}\mathrm{i}}{8\mathrm{R}}$