Network access devices $($such as network switches and wireless access points$)$ can use an IEEE protocol that when enabled, will allow traffic on the port only after the device has been authenticated and authorized. Which of the following is an IEEE standard that is used to implement port$-$based access control?

A $,802\mathrm{.}1x$

B pxGrid

C $802\mathrm{.}11$ ac

D BYOD