What must be present if the mask parameter is specified for BGP?

• A. It will advertise only if the route has a next-hop-self override
• B. The routing table must contain a default route
• C. It will advertise regardless of any routing table entry
• D. An exact match to both network and mask must be present in the IP routing table in order for BGP to advertise the network

Answer: (D)

When a BGP network statement includes a subnet mask, the router will advertise that network into BGP only if there is an exact match for both the network address and the mask in the IP routing table. This exact-match requirement ensures the route is actually present and eligible for redistribution into BGP as the specified subnet. If there’s no routing-table entry that matches that precise network and mask, BGP won’t advertise it, even if other routes or a default route exist. The other statements listed don’t reflect this behavior because they either relate to unrelated features (like next-hop behavior) or to conditions that don’t govern whether a network with a mask is advertised.