Which of the following about an LSP protected with facility FRR is TRUE?

Facility FRR, also known as many-to-one backup, is a scalable local protection mechanism. It allows a single pre-established protection tunnel (a "facility" or bypass tunnel) to be shared by multiple primary LSPs that traverse the same potential point of failure (link or node). When one of the protected LSPs fails, its traffic is switched to this common, shared protection tunnel. This contrasts with one-to-one backup, where a dedicated detour tunnel is created for each individual primary LSP.

B. An LSP uses either facility or one-to-one FRR for a given failure scenario at a Point of Local Repair (PLR), based on configuration preference, not both simultaneously.
C. Facility FRR can provide both link protection (bypassing a failed link) and node protection (bypassing a failed downstream router), it is not limited to link protection.
D. A dedicated detour protection tunnel created for a single LSP is the definition of one-to-one FRR, not facility FRR, which relies on a shared tunnel.

Nokia 7750 SR OS MPLS Guide, Release 22.10.R1, Section: Facility Backup Method. "With facility backup, a single bypass tunnel can be used to protect a group of LSPs. The bypass tunnel terminates at a node downstream of the potential failure point."

RFC 4090, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", Section 4.2. "Facility" Backup. "In this approach, one or more label-switched paths are created to serve as bypass tunnels... A bypass tunnel can protect a set of LSPs that have similar path characteristics."