What is the status of the L2 tunnel between PE1, PE2 and the layer 2 switches?

Refer to the exhibit.

What is the status of the L2 tunnel between PE1, PE2 and the layer 2 switches?
A . The layer 2 tunnel is down due to the ACL is applied on the PE2 interface
B . The layer 2 tunnel is up and SW1 become the root bridge for VLAN 10
C . The layer 2 tunnel is down due to the MTU mismatch between SW1 and SW2
D . The layer 2 tunnel is up but no BPDUs are exchange unless an extra configuration is applied

View Answer

Answer: B