In an MST region, MSTP independently calculates an MSTI for each VLAN based on mappings...

A is false – Ports in MSTP can have different roles and states in different MSTIs. Each MSTI can independently elect a root and compute its own topology, which results in different port states per MSTI .

B is true – MSTIs use the same spanning tree algorithm as STP (and RSTP) for calculating the spanning tree topology.

C is true – Each MSTI may have a different root bridge and separate topology, depending on VLAN mappings.

D is true – MSTIs do not independently send BPDUs; only MSTI 0 (CIST) actually sends BPDUs, and information about other MSTIs is encapsulated within it. So the statement is worded to test conceptual understanding , but not incorrect in MSTP context as framed.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“MSTP allows different MSTIs to have different topologies. A port may be forwarding in MSTI 1 but blocking in MSTI 2. This independence improves VLAN-based traffic engineering.”

(Chapter: MSTP Concepts – Section: MSTI Behavior and Port Roles)