IP routing protocols, such as OSPF and Enhanced EIGRP, are used primarily in network designs that contain entry and exit points to the network from service providers. What is a common trait of IP routing protocols?

A.
They are essential for optimum and redundant forwarding.

B.
They are usually necessary in smaller deplpyments.

C.
They are used primarily in large network designs, to support different networks and single entry and exit points.

D.
They add needed overhead in small deployments.