An administrator is unsuccessful in adding VLAN 50 to a switch. While troubleshooting the problem，the administrator views the output of the show vtp status command， which is displayed in the graphic. What commands must be issued on this switch to add VLAN 50 to the database？（）

• A、 Switch（config-if）# switchport access vlan 50
• B、 Switch（vlan）# vtp server
• C、 Switch（config）# config-revision 20
• D、 Switch（config）# vlan 50 name Tech
• E、 Switch（vlan）# vlan 50
• F、 Switch（vlan）# switchport trunk vlan 50