Which statement about MPLS LDP router ID is true?

The `force` keyword, while existing in some router ID configurations, does not define LDP's default router ID selection process, and its impact is generally related to immediate application rather than defining the ID itself.

By default, if an LDP router ID is not explicitly configured, LDP selects the highest IP address of an active loopback interface as its router ID. If no loopback interfaces are configured, it then chooses the highest IP address of any active physical interface on the router, ensuring a stable and unique identifier for LDP peering.

This statement is incorrect because loopback interfaces are always preferred over physical interfaces for LDP router ID selection due to their reliability and 'always up' status.

The MPLS LDP router ID does not technically have to match the IGP router ID; while often recommended for operational consistency, it is not a protocol requirement.