Open the PT Activity. Perform the tasks in the activity instructions and then answer the question. What is the problem preventing PC0 and PC1 from communicating with PC2 and PC3?
A. The routers are using different OSPF process IDs.
B. The serial interfaces of the routers are in different subnets.
C. No router ID has been configured on the routers.
D. The gigabit interfaces are passive.