Refer to the exhibit. Router A must reach Router X. Which option describes how router A decides which interface to use to forward packets?

Per-flow load balancing requires two or more equal-cost paths to exist in the RIB simultaneously; with unequal-cost paths the RIB installs only one route, so no load balancing occurs.

The RIB (Routing Information Base) is the authoritative routing table that selects the single best path based on metric and administrative distance; when equal-cost paths are not present, the RIB holds one route with one outgoing interface, which is what Router A consults to make its forwarding decision.

The FIB is built from the RIB and used by CEF for fast hardware-level lookups; it reflects what the RIB has already decided rather than making an independent interface selection, so the RIB is the correct source of the forwarding decision.

Per-packet load balancing distributes individual packets round-robin across equal-cost paths; like per-flow balancing, it is only possible when multiple equal-cost routes exist in the RIB, which the exhibit does not show.