What is one benefit of the root protection feature?

A.
It guards against loops caused by unidirectional link failures.

B.
It ensures downstream switches never become the root bridge.

C.
It disables the port when it detects that a loop has formed over an edge port.

D.
It guards against loops caused by a changed root bridge ID.

Explanation:
Root Protection for Spanning-Tree Instance Interfaces Overview

Root protect helps to enforce the root bridge placement in a Layer2 switched network. Enable root protect on interfaces that should not receive superior bridge protocol data units (BPDUs) from the root bridge. Typically, these ports are Spanning-Tree-Protocol-designated ports on an administrative boundary. Enabling root protect ensures the port remains a spanning-tree designated port.

If the bridge receives superior BPDUs on a port that has root protect enabled, that port transitions to a root-prevented STP state and the interface is blocked. This prevents a bridge that should not be the root bridge from being elected the root bridge.

After the bridge stops receiving superior BPDUs on the port with root protect enabled and the received BPDUs time out, that port transitions back to the STP-designated port state.