Border Gateway Protocol is the best answer when considering BGP’s internal administrative distance value. Administrative distance is used by routers to decide which route source is more trustworthy when multiple routing sources advertise a path to the same destination. Lower values are preferred. A static route normally has an administrative distance of 1, internal EIGRP is commonly 90, OSPF is 110, external EIGRP is 170, external BGP is 20, and internal BGP is 200.
The CompTIA Network+ N10-009 objectives include routing protocol behavior, dynamic routing, route selection, and administrative distance. Because internal BGP has an administrative distance of 200, BGP can have the highest administrative distance among the listed options.
This question is slightly tricky because BGP has different administrative distance values depending on whether the route is learned through external BGP or internal BGP. If a question specifically said external BGP, its value would be 20, which would not be the highest. However, among the listed technologies, BGP is the best exam-style answer because iBGP has the highest default administrative distance listed here.
