Which of the following Wi-Fi standards operates over the 5GHz band?

The Wi-Fi standard that operates over the 5GHz band is 802.11a. This standard was developed to provide higher data rates, typically up to 54 Mbps, and it specifically utilizes the 5GHz frequency range, which allows for less interference compared to the 2.4GHz band used by other standards. This ability to operate on the 5GHz band means that 802.11a can offer improved performance, particularly in environments with many competing signals, making it a more efficient choice for reducing congestion in wireless networks.

In terms of context, 802.11b and 802.11g primarily operate over the 2.4GHz band, leading to susceptibility to interference from common household devices such as microwaves and Bluetooth devices. On the other hand, while 802.11n can operate on both the 2.4GHz and 5GHz bands, its capability to run on the 5GHz band is not definitive like that of 802.11a. 802.11n is designed for backward compatibility and can deliver higher speeds and increased range by utilizing multiple antennas (MIMO technology), but it is not solely a 5GHz standard as 802.11a is.