A particle of mass $m$ and charge $Q$ moving with velocity $\vec{\nabla}$ describes a circular path of radius $R$ when subjected to a uniform transverse magnetic field of inductance $B_{2}$
The work done by the field when the particle completes one full circle is :
(a) $B Q v(2 \pi R)$
(b) $\left(\frac{m v^{2}}{R}\right) 2 \pi R$
(c) zero
(d) $B Q(2 \pi R)$