What caused this problem?

Refer to the exhibit. After SwitchB was added to the network, VLAN connectivity problems started to occur. What caused this problem?

A.
Both switches are in sever mode in the same domain

B.
The revision number of SwitchB was higher than the revision number of SwitchA

C.
SwitchA was not rebooted prior to adding SwitchB to the network.

D.
V2-mode is not enabled.

E.
VTP pruning is not activated, so the new paths in the network have not been recalculated.