In a traditional 3 tier topology, an engineer must explicitly configure a switch as the root bridge and exclude it from any further election process for the spanning-tree domain. Which action accompli

Configuring the spanning-tree priority to 32768 sets it to the default priority, which does not guarantee it will become the root or protect its root status.

Configuring root guard on all access switch ports prevents those ports from becoming root ports if they receive superior BPDUs, effectively ensuring the designated root bridge remains the root and is excluded from further elections by other switches.

Configuring BPDU guard on switch-to-switch connections is a misconfiguration as it would shut down these critical links upon receiving BPDUs, breaking STP functionality.

Configuring the spanning-tree priority equal to 0 makes a switch the root bridge by giving it the lowest possible priority, but it does not actively prevent other switches from attempting to become root through superior BPDUs; root guard provides this protective mechanism.