An architect is designing a network that will utilize the spanning tree protocol to ensure a loop-free topology. The network will support an engineering environ...

An architect is designing a network that will utilize the spanning tree protocol to ensure a loop-free topology. The network will support an engineering environment where it is necessary for end-users to connect their own network switches for testing purposes. Which feature should the architect include in the design to ensure the spanning-tree topology is not affected by these rogue switches?

A. BPDU Skew Detection B. BPDU guard C. loop guard D. root guard