Explanation/Reference:
Explanation:
To form neighbor relationship in EIGRP, these conditions must be met:
* Pass the authentication process
* Have the same configured AS number
* Must believe that the source IP address of a received Hello is in that router's primary connected subnet on that interface
* Match K values
The third item means that the primary ip address of the neighbor must be in the same subnet with the primary ip address of the received interface. But in this case the primary ip address of router A is
10.10.10.1/30 and it is not in the same subnet with the primary ip address of router B 10.10.10.6/30 -> no EIGRP neighbor relationship is formed.