A portion of a conductive wire is bent in the form of a semicircle of radius r as shown below in fig. At the centre of semicircle, the magnetic induction will be

• A

  zero

• B

  infinite

• C

  $\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\cdot \frac{\mathrm{\pi i}}{\mathrm{r}}$gauss

• D

  $\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\cdot \frac{\mathrm{\pi i}}{\mathrm{r}} \mathrm{tesla}$