Fault Condition is related to which technology?

Fault Condition is related to which technology?
A . BGP
B . NTP
C . IP NAT
D . IPv4 OSPF Routing
E . IPv4 OSPF Redistribution
F . IPv6 OSPF Routing
G . IPv4 layer 3 security

Answer: D

Explanation:

The problem in this situation is with OSPF on router 1. It is missing the "ip ospf authentication messagedigest" command on the Serial0/0/0/0.12 interface. The problem statement tells us that the two routers are not able to become OSPF neighbors.