WiFi stands for Wireless Fidelity. WiFi is the marketing name for the IEEE standard 802.11. It is a standard for both Level 1 (physical) and Level 2 (data link) of a wireless data transmission protocol.802.11 ? This pertains to wireless LANs and provides 1- or 2-Mbps transmission in the 2.4-GHz band using either frequency-hopping spread spectrum (FHSS) or direct-sequence spread spectrum (DSSS).802.11a ? This is an extension to 802.11 that pertains to wireless LANs and goes as fast as 54 Mbps in the 5-GHz band. 802.11a employs the orthogonal frequency division multiplexing (OFDM) encoding scheme as opposed to either FHSS or DSSS.802.11b ? The 802.11 high rate WiFi is an extension to 802.11 that pertains to wireless LANs and yields a connection as fast as 11 Mbps transmission (with a fallback to 5.5, 2, and 1 Mbps depending on strength of signal) in the 2.4-GHz band. The 802.11b specification uses only DSSS. Note that 802.11b was actually an amendment to the original 802.11 standards added in 1999 to permit wireless functionality to be analogous to hard-wired Ethernet connections.802.11g ? This pertains to wireless LANs and provides 20+ Mbps in the 2.4-GHz band.802.11i - It is an IEEE 802.11 amendment used to facilitate secure end-to-end communication for wireless local area networks (WLAN). IEEE 80211i improves mechanisms for wireless authentication, encryption, key management and detailed security.Therefore Answer is Option 4