正解:B
The tag that defines the roaming domain and properties of an AP deployment is known as a policy tag. Policy tags are used to assign specific policies to groups of APs, which can include settings related to security, QoS, and other operational parameters. These tags help manage and enforce consistent policies across the wireless network, facilitating efficient roaming and network management.
References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) training materials