Which $802\mathrm{.}11$ authentication method requires the use of WEP $($Wired Equivalent Privacy$)?$ A IEEE $802\mathrm{.}11$ open system B RADIUS C IEEE $802\mathrm{.}11$ shared $-$key D IEEE $802\mathrm{.}1$X $/$EAP E WPA $2\mathrm{.}0$