Based on the exhibit, which two statements are true? (Choose two.)
A.
Sw-1 and Sw-2 both claim to be MSTI 1and MSTI 2 root bridges; VLAN-to-instance fields will not match in the BPDU’s MSTI fields.
B.
Both Sw-1 and Sw-2 are in different MSTP regions.
C.
Sw-2 will calculate Sw-1 as CST root.
D.
Sw-1 and Sw-2 will each claim to be CST root.
Why not A and B? A is true. In order for them to be in the MSTI 1 as configured, the VLAN-to-instance fields must match but this is not the case. So A is true.
http://www.juniper.net/techpubs/en_US/junos/topics/concept/mx-series-multiple-stp.html
There is a common spanning-tree (CST) instance that spans all regions and allows different regions to communicate between themselves. The CST is also used for traffic within the region for any VLANs not covered by an MSTI.