You have configured a Cisco Catalyst switch to perform Layer 3 routing via an SVI and have 
assigned that interface to VLAN 20. To check the status of the SVI， you issue the show interfaces vlan 20 command at the CLI prompt. You see from the output display that the interface is in an "up/up" state. 
What must be true in an SVI configuration to bring the VLAN and line protocol up？（）

A.The best match of the ACL entries will be used for granularity of control.
B.They use source IP information for matching operations.
C.They use source and destination IP information for matching operations.
D.They use source IP information along with protocol-type information for finer granularity of control.

A.Enable the switch to participate in routing updates from external devices with the router command in global configuration mode.
B.Enter the no switchport command to disable Layer 2 functionality at the interface level.
C.Each port participating in routing of Layer 3 packets must have an IP routing protocol assigned on aperinterface level.
D.Routing is enabled by default on a multilayer switch， so the port can become a Layer 3 routing interface by assigning the appropriate IP address and subnet information.

A.ease of IP address assignment versus use of external routers
B.redundancy from trunking between distribution layer switches
C.provides first-hop redundancy to clients
D.allows inter-VLAN communication without requiring complexity of routing protocols