正解:A
MACsec, defined by IEEE standard 802.1AE, is a security technology that provides encryption, integrity, and authentication for data on Ethernet networks.
It ensures that only authorized devices can access and modify the transmitted data, thereby protecting against threats like interception and tampering.
MACsec operates at Layer 2 of the OSI model, which means it secures data at the link level between devices such as switches and hosts.
Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-9/configur