A router holds four routes that all match the destination 10.1.1.5: a connected route to 10.0.0.0/8, an OSPF route to 10.1.0.0/16, an EIGRP route to 10.1.1.0/24, and a static default route 0.0.0.0/0. By default, which route does the router use to forward the packet?
- AThe OSPF route to 10.1.0.0/16, because OSPF has a lower administrative distance than EIGRP
- BThe connected route to 10.0.0.0/8, because connected routes have the lowest administrative distance of 0
- CThe static default route 0.0.0.0/0, because static routes are preferred over dynamic routes
- DThe EIGRP route to 10.1.1.0/24, because it is the longest prefix that matches the destination Correct
Why A is wrong: Administrative distance is tempting here, but it only breaks ties between routes to the SAME prefix; with different prefix lengths the longest match is chosen first, so the /16 is never compared by AD.
Why B is wrong: A connected route does have AD 0, but administrative distance is not consulted until after longest prefix match; the /8 is the least specific of the matches, so it loses on prefix length.
Why C is wrong: Static routes do carry a low AD of 1, but the default route is the least specific match of all; longest prefix match selects a more specific entry whenever one exists.
Why D is correct: Longest prefix match is the first and decisive test: /24 covers 10.1.1.5 and is more specific than /16, /8, or the default, so this route is installed for forwarding regardless of AD or metric.