Which two statements about BPDU guard are true? (Choose two.)
A. The global configuration command spanning-tree portfast bpduguard default shuts down interfaces that are in the PortFast-operational state when a BPDU is received on that port.
B. The interface configuration command spanning-tree portfast bpduguard enable shuts down only interfaces with PortFast enabled when a BPDU is received.
C. BPDU guard can be used to prevent an access port from participating in the spanning tree in the service provider environment.
D. BPDU guard can be used to protect the root port.
E. BPDU guard can be used to prevent an invalid BPDU from propagating throughout the network.
