Which two best practices does Cisco recommend to migrate a network from PVST+ to MST?

Which two best practices does Cisco recommend to migrate a network from PVST+ to MST? (Choose two.)
A. Start the migration at the edge nodes and work toward the root bridge.
B. Before starting the transition, configure one of the edge nodes with a lower priority so that it becomes the root bridge after the transition.
C. Before starting the transition, ensure that at least two nodes act as the root bridge for all VLANs in the network.
D. Start the migration at the root bridge and work toward the edge nodes.
E. Before starting the transition, configure one of the edge nodes with a higher priority so that it becomes the root bridge after the transition.
F. Before starting the transition, ensure that one node is the root bridge for all VLANs in the network.