单项选择题
如下图所示,3com和Cisco公司的交换机相互连接,在两台交换机之间需传输VLAN ID为1、10、20和30的4个VLAN信息,Catalyst 3548交换机VLAN Trunk的正确配置是______。

A.Switch-3548(config-if)#switchport trunk encapsulation dotl qSwitch-3548(config-if)#switehport trunk allowed vlan 1,10,20,30
B.Switch-3548(config-if)#switchport mode trunkSwitch-3548(config-if)#switchport trunk encapsulation is1Switch-3548(config-if)#switchport trunk allowed vlan 1-30
C.Switch-3548(config-if)#switchport mode trunkSwitch-3548(config-if)#switchport trunk encapsulation negotiateSwitch-3548(config-if)#switehport trunk allowed vlan 1-30
D.Switch-3548(config-if)#switchport mode trunkSwitch-3548(config-if)#switchport trunk encapsulation dot1 qSwitch-3548(config-if)#switchport trunk allowed vlan 1,10,20,30