While logged into a Company switch you issue the following command：   CompanySwitch（config-mst）# instance 10 vlan 11-12   What does this command accomplish？（）

• A、 It enables a PVST+ instance of 10 for vlan 11 and vlan 12
• B、 It enables vlan 11 and vlan 12 to be part of the MST region 10
• C、 It maps vlan 11 and vlan 12 to the MST instance of 10.
• D、 It creates an Internal Spanning Tree （IST） instance of 10 for vlan 11 and vlan 12  
• E、 It create a Common Spanning Tree （CST） instance of 10 for vlan 11 and vlan 12
• F、 It starts two instances of MST， one instance for vlan 11 and another instance for vlan 12.