Final answer:
The correct answer is options B. 802.11b, C. 802.11g, and D. 802.11n. The WLAN standards that operate in the 2.4 GHz frequency band are 802.11b, 802.11g, and 802.11n. The 802.11a standard operates exclusively in the 5 GHz band.
Step-by-step explanation:
These WLAN standards can all operate in the 2.4 GHz frequency band. To clarify, 802.11a operates in the 5 GHz band and is therefore not included. Equipment using 802.11b or 802.11g standards exclusively utilizes the 2.4 GHz band, and while 802.11n is capable of operating in both the 2.4 GHz and 5 GHz bands, it is nonetheless included because of its ability to operate at 2.4 GHz.
The 802.11b standard operates in the 2.4 GHz frequency band. This standard provides a data transfer rate of up to 11 Mbps. It was one of the earliest wireless LAN standards and is still used in some older devices today.
The other options, 802.11a, 802.11g, and 802.11n, operate in different frequency bands. 802.11a operates in the 5 GHz band, while 802.11g and 802.11n can operate in both the 2.4 GHz and 5 GHz bands.