A proton $($charge e$),$ traveling perpendicular to a magnetic field, experiences the same force as an alpha particle $($charge $2$e$)$ which is also traveling perpendicular to the same field. The ratio of their speeds, Vpro$/$Valpha $18$: A$)0\mathrm{.}5$ B$)1$ C$)2$ D$)4$ E$)8$