单项选择题
A. prefer EBGP over IBGP, prefer routes from the lowest RID, prefer routes with lowest IGP metric
B. prefer routes from the lowest RID, prefer routes with lowest IGP metric, prefer EBGP over IBGP
C. prefer routes with lowest IGP metric, prefer routes from the lowest RID, prefer EBGP over IBGP
D. prefer EBGP over IBGP, prefer routes with lowest IGP metric, prefer routes from the lowest RID