Axis of a solid cylinder of infinite length and radius R lies along y-axis. It carries a uniformly distributed current I along +y direction. Magnetic field at a point (R/2, y, R/2) is

• A

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{4\mathrm{\pi R}}\left(\widehat{\mathrm{i}}-\widehat{\mathrm{k}}\right)$

• B

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{2\mathrm{\pi R}}\left(\widehat{\mathrm{i}}-\widehat{\mathrm{k}}\right)$

• C

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{4\mathrm{\pi R}}\widehat{\mathrm{j}}$

• D

  $\frac{{\mathrm{\mu }}_0\mathrm{I}}{4\mathrm{\pi R}}\left(\widehat{\mathrm{i}}+\widehat{\mathrm{k}}\right)$