A Cisco engineer must configure a single switch interface to meet these requirements:
* Accept untagged frames and place them in VLAN 20
* Accept tagged frames in VLAN 30 when CDP detects a Cisco IP phone
Which command set must the engineer apply?

A. switchport mode dynamic desirable
switchport access vlan 20
switchport trunk allowed vlan 30
switchport voice vlan 30
B. switchport mode access
switchport access vlan 20
switchport voice vlan 30
C. switchport mode dynamic auto
switchport trunk native vlan 20
switchport trunk allowed vlan 30
switchport voice vlan 30
D. switchport mode trunk
switchport access vlan 20
switchport voice vlan 30