The current in an electron beam in a cathode$-$ray tube is measured to be $50$A$.$ How many electrons hit the screen in $7\mathrm{.}0$ s$?($e $=1\mathrm{.}61019$ C$)$

a$.$

$2\mathrm{.}21015$ electrons

b$.$

$3\mathrm{.}11018$ electrons

c$.$

$3\mathrm{.}51013$ electrons

d$.$

$4\mathrm{.}41011$ electrons

e$.$

$2\mathrm{.}71017$electrons