Which of the following Wi-Fi standards can support legacy devices on the 2.4 GHz band?

The correct answer is 802.11n because this standard is designed to be backward compatible with older Wi-Fi standards, such as 802.11g and 802.11b. This means that devices that operate on the 2.4 GHz band, which includes legacy devices using 802.11b and 802.11g, can connect to an 802.11n network without any issues.

Additionally, 802.11n can utilize multiple input and output (MIMO) technology, which enhances performance and range. It can operate on both the 2.4 GHz and 5 GHz bands, allowing it to work in environments where legacy devices are present while still providing improved speed and connectivity options for newer devices.

Regarding the other standards, 802.11a operates solely on the 5 GHz band and does not support legacy devices on the 2.4 GHz band. Meanwhile, 802.11g, although it can support legacy devices, is not as versatile as 802.11n concerning improved performance and compatibility with newer technology. The choice labeled simply as 802 is not a recognized Wi-Fi standard, making it invalid in this context.