Refer to the exhibit A new VLAN and switch are added to the network. A remote engineer configures OldSwitch and must ensure that the configuration meets these requirements:

* accommodates current configured VLANs
* expands the range to include VLAN 20
* allows for IEEE standard support for virtual LANs

Which configuration on the NewSwitch side of the link meets these requirements?

A. switch port mode dynamic
channel group 1 mode active
switchport trunk allowed vlan 5,10,15, 20 B. no switchport mode trunk
switchport trunk encapsulation isl
switchport mode access vlan 20 C. switchport nonegotiate
no switchport trunk allowed vlan 5,10
switchport trunk allowed vlan 5,10,15,20 D. no switchport trunk encapsulation isl
switchport trunk encapsulation dot1q
switchport trunk allowed vlan add 20