Which of the following would be good reasons to run NAT?
1.You need to connect to the Internet and your hosts don't have globally unique IP addresses.
2.You change to a new ISP that requires you to renumber your network.
3.You don't want any hosts connecting to the Internet.
4.You require two intranets with duplicate addresses to merge.
Answer: A
The most popular use of NAT is if you want to connect to the Internet and you don't want hosts to have global (real) IP addresses, but option B and D are correct as well.