Which three statements about the Multiple Spanning Tree (MST) protocol (IEEE 802.1s) are true? (Choose three.)
A. An MST region is a group of MST switches that appear as a single virtual bridge to adjacent CST and MST regions.
B. All switches in an MST region, except distribution layer switches, should have their priority lowered from the default value 32768.
C. All switches in the same MST region must have the same VLAN-to-instance mapping, but different configuration revision numbers.
D. Enabling MST with the spanning-tree mode mst global configuration command also enables RSTP.
E. To verify the MST configuration, the show pending command can be used in MST configuration mode.
F. When RSTP and MSTP are configured, UplinkFast and BackboneFast must also be enabled.