Scenario:
A customer network engineer has edited their OSPF network configuration and now your customer
is experiencing network issues. They have contacted you to resolve the issues and return the
network to full functionality.

After resolving the issues between R3 and R4. Area 2 is still experiencing routing issues. Based
on the current router configurations, what needs to be resolved for routes to the networks behind
R5 to be seen in the company intranet?

A.
Configure R4 and R5 to use MD5 authentication on the Ethernet interfaces that connect to the
common subnet.

B.
Configure Area 1 in both R4 and R5 to use MD5 authentication.

C.
Add ip ospf authentication-key 7 BEST to the R4 Ethernet interface that connects to R5 and ip
ospf authentication-key 7 BEST to R5 Ethernet interface that connects to R4.

D.
Add ip ospf authentication-key CISCO to R4 Ethernet 0/1 and add area 2 authentication to the
R4 OSPF routing process.

Explanation:
Here, we see from the running configuration of R5 that OSPF authentication has been configured
on the link to R4:

However, this has not been done on the link to R5 on R4: