Refer to the exhibit. What is causing the error to occur on the MST switch?
A. When a PVST+ switch is connected to an MST switch, the IST root (MST0) needs to be the root for all PVST+ spanning trees.
B. When a PVST+ switch is connected to an MST switch, interaction between MST and PVST+ is not supported
C. When a PVST+ switch is connected to an MST switch, root guard should be disabled on a per-port basis.
D. When a PVST+ switch is connected to an MST switch, the PVST+ switch must be the root for all MST instances.
