An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii $r_e, r_p, r_{\alpha}$ respectively in unifrom magnetic field B. The relation between $r_e, \; r_p, \; r_\alpha$ is :

Question

( A ) $r_e < r_p = r_{\alpha}$
( B ) $r_e < r_p < r_{\alpha}$
( C ) $r_e < r_{\alpha} < r_p$
( D ) $r_e > r_p = r_{\alpha}$