6. B is correct. Although the RFC does not specify how cost is determined, Cisco defaults to a value that is inversely proportional to 100Mbps. Although the capacity of the line is 1Mbps, the router cannot detect this and assumes the default bandwidth of roughly 1.5Mbps. The fraction 100Mbps / 1.5Mbps rounds down to a value of 64.

8. A and B are correct. When using the “ip route command”, you can specify an IP address as the next hop, or an interface out which to send the packet.

9. B and C are correct. Since care was taken during the design phase, it is possible to simply add a new subnet to the branch office by adding a secondary IP address to the LAN interface of the router at the branch office. Also, a larger subnet could be assigned, which may or may not be difficult, depending on whether any static IP addresses are configured.

10. C is correct. R1, R2, and R3 will become neighbors and exchange routing information. R3's “network 10.1.1.0 0.0.0.255” command uses the wildcard mask option, meaning that all interfaces beginning with an IP address of "10.1.1" will match. R4 uses a mask like a subnet mask; however, the mask in the EIGRP network command acts like an ACL wildcard mask. In this case, R4 would match all interfaces whose IP address ends in 0.