Circular loop of a wire and a long straight wire carrying current $\mathrm{I}_{\mathrm{C}}, \mathrm{I}_{\mathrm{E}}$ respectively as shown in fig. Assuming that these are placed in the same plane. The mag. field will be zero at the centre of the Loop when separation $\mathrm{H}$ is
(a) $\left[\left(\mathrm{I}_{\mathrm{e}} \mathrm{R}\right) /\left(\mathrm{I}_{c} \pi\right)\right]$
(b) $\left[\left(\mathrm{I}_{\mathrm{c}} \mathrm{R}\right) /\left(\mathrm{I}_{\mathrm{e}} \pi\right)\right]$
(c) $\left[\left(\pi \mathrm{I}_{\mathrm{c}}\right) /\left(\mathrm{I}_{\mathrm{e}} \mathrm{R}\right)\right]$
(d) $\left[\left(\mathrm{I}_{\mathrm{e}} \pi\right) /\left(\mathrm{I}_{\mathrm{c}} \mathrm{R}\right)\right]$