Spanning-Tree RootGuard

Hi Andrew,

In the same topology, assume that bpdu guard is configured on access switches interfaces to hosts, root guard is configured on distribution switches interfaces to access switches, and core switches interfaces to distribution switches. If your example 1) a new Distribution switch is plugged in with a superior BPDU would happen:
1)How would it change the entire spanning-tree topology? Could you give the steps how would it be root bridge?
2)Would our core switch which was root before, would remain root, or would it start to see new distribution switch as a root?
3)What would be the effect of root guard configuration on core switch interface to distribution switch interface on this case?
BR
Umut