Wi$-$Fi Host A$,$ with MAC address WH$-$A$,$ sends a datagram with an HTTP request payload to google.com, MAC address G$-$M$.$ In the wireless network the access point has MAC address AP$-$M$,$ and is connected via Ethernet to the gateway router, MAC address GR$-$M$.$ The MAC protocol used to send the IEEE $802\mathrm{.}11$ frame is $\_\_\_.$

a$.$

CSMA$/$CA

b$.$

CSMA$/$CD

c$.$

CDMA

d$.$

FDMA

e$.$

TDMA