Regarding the stpmcheck command in spanning tree configuration, which of the following are the correct statements?

Regarding the stpmcheck command in spanning tree configuration, which of the following are the correct statements?
A . This command is used when RSTP switches and MSTP switches are interconnected.
B . This command is used when switches from different manufacturers are interconnected and MSTP is running to check summary information.
C . This command is used when the switch port running RSTP or MSTP is connected to the STP device.
D . By running this command on a port of an RSTP or MSTP switch, you can switch the spanning tree mode of the port to STP.

Answer: C