2016 on 21 net work OSPF network is divided into a variety of areas, including as regional between exchange routing information is (),
A. the trunk area b. c. standard area stub areas d. don't stub area
The answer is A
Analytic:
In order to make the OSPF can be used for large scale network, OSPF to an autonomous system is divided into several smaller range, called area, the advantages of dividing area, is for the exchange of link-state information using the method of flood limit in an area, rather than the entire autonomous system, reduces the network traffic, in the region is in a router only know about this area of the complete topology, and don't know the whole area of the network topology,
In order to make every area to communicate and the region outside of the area, OSPF USES hierarchical division, in the upper area of the region is called the trunk, trunk area specified as 0.0.0.0 identifier, its effect is connected in the area of the lower, other information from other area are made by area border router to generalize,

But I didn't feel the above analytic said to exchange routing information, don't know what do you understand??