Even before this question is answered, it is best that you understand what an OSPF is. This stands for Open Shortest Path First. This is a type of routing protocol that some networks use. This can make it easier for group connected routers to be identified and established. This can make the management of the routers easier to do.
It will also help optimize the various resources that are available. Going back to the question, the right answers are letter A, letter C, and letter E. Options A and C are already obvious and would not need further explanation. Some are not aware why E is correct. This will help improve the total control of the routers for better management.
It supports VLSM. It confines network instability to one area of the network. It allows extensive control of routing updates
Answer A and C are obviously correct. For answer E, it allows extensive control of routing updates via Link-State Advertisement (LSA). Administrators can filter these LSAs to meet their requirements easily.