正解:A
The origin code in BGP indicates where a route originated from. By default, when a route is
injected into BGP using the network command, the origin code is i (IGP). If the origin is set to
something else (e.g., incomplete), the BGP attributes may not behave as expected.
In this case, to ensure that R1 receives the routes from R7 with the origin code as i, a route-map
needs to be applied on R7 to modify the origin attribute for the specified routes. The set origin igp
command in the route-map modifies the origin code for the routes matched by the access list.