A circular loop made of thin copper wire of mass ' \(\mathrm{m}\) ' is placed in a uniform magnetic field such that the plane of the loop is perpendicular to the magnetic field. If ' \(d\) ' and ' \(\rho\) ' are the density and resistivity of copper respectively and the magnetic field varies at a constant rate of \(\frac{\mathrm{dB}}{\mathrm{dt}}\), then the induced current in the loop is ____

1. A \(\frac{4 \pi \mathrm{m}}{\rho \mathrm{d}}\left(\frac{\mathrm{dB}}{\mathrm{dt}}\right)\)
2. B \(\frac{4 \mathrm{~m}}{\pi \rho \mathrm{d}}\left(\frac{\mathrm{dB}}{\mathrm{dt}}\right)\)
3. C \(\frac{\pi \mathrm{m}}{4 \rho \mathrm{d}}\left(\frac{\mathrm{dB}}{\mathrm{dt}}\right)\)
4. D \(\frac{\mathrm{m}}{4 \pi \rho \mathrm{d}}\left(\frac{\mathrm{dB}}{\mathrm{dt}}\right)\)