$16)$ An electron is accelerated from rest through a potential difference of $3\mathrm{.}75$ kV$.$ It enters a region where a uniform $4\mathrm{.}0-$mT magnetic field is perpendicular to the velocity of the electron. Calculate the radius of the path this electron will follow in the magnetic field. $($e $=1\mathrm{.}6010-19$ C$,$ melectron $=9\mathrm{.}1110-31$ kg$)$ A$)1\mathrm{.}2$ cm B$)2\mathrm{.}2$ cm C$)3\mathrm{.}2$ cm D$)4\mathrm{.}2$ cm E$)5\mathrm{.}2$ cm