R1 has learned route 192.168.12.0/24 via IS-IS, OSPF, RIP, and Internal EIGRP. Under normal operating conditions, which routing protocol is installed in the routing table? 

Answer options:

A. IS-IS
B. Internal EIGRP
C. RIP
D. OSPF

B

With the same route (prefix), the router will choose the routing protocol with lowest Administrative Distance (AD) to install into the routing table. The AD of Internal EIGRP (90) is lowest so it would be chosen. The table below lists the ADs of popular routing protocols. 

Note: The AD of IS-IS is 115. The EIGRP in the table above is Internal EIGRP. The AD of External EIGRP is 170. An EIGRP external route is a route that was redistributed into EIGRP.