Which statement describes Cisco PfR link groups?
A. Link groups enable Cisco PfR Fast Reroute when NetFlow is enabled on the external interfaces of the border routers.
B. Link groups define a strict or loose hop-by-hop path preference.
C. Link groups are required only when Cisco PfR is configured to load-balance all traffic.
D. Link groups are enabled automatically when Cisco PfR is in Fast Reroute mode.
E. Link groups set a preference for primary and fallback (backup) external exit interfaces.
