Which change will ensure that Switch1 will be selected as the root bridge instead of Switch9?

The switches on a campus network have been interconnected as shown. All of the switches are running Spanning Tree Protocol with its default settings. Unusual traffic patterns are observed and it is discovered that Switch9 is the root bridge. Which change will ensure that Switch1 will be selected as the root bridge instead of Switch9?

A.
Raise the bridge priority on Switch1.

B.
Lower the bridge priority on Switch9.

C.
Raise the bridge priority on Switch9.

D.
Physically replace SwitchQ with Switchl in the topology.

E.
Disable spanning tree on Switch9.

F.
Lower the bridge priority on Switch1.

Explanation:
The root bridge is the bridge or switch that is the root of the Spanning Tree, with the branches being loop-free paths to the other switches in the system. The Root is the switch with the lowest Bridge ID; the ID is determined by a combination of an administrative Priority and the MAC address of the switch. The Priority is set to 32,768 (8000 hex) by default; if we leave the Priority at the default, whatever switch has the lowest MAC will be the Root. So to elect the Switchl switch as a root bridge need to set the lowest priority.