Which AP mode allows APs to register to a WLC so the controller centrally switches traffic?

The local mode is the default and most common AP mode. In local mode, the AP registers with the Wireless LAN Controller (WLC), and all client traffic is encapsulated and sent to the WLC via a Control And Provisioning of Wireless Access Points (CAPWAP) tunnel. The WLC then centrally switches or routes this traffic. Bridge mode is used for wireless bridging between two wired networks. FlexConnect mode allows APs to locally switch client data traffic when the WLC is unreachable, providing resilience for branch offices. Fabric mode is a newer concept related to Cisco Software-Defined Access (SDA) and is not a traditional AP operating mode for central traffic switching by a WLC.