NAT is not perfect, but there are some advantages. It conserves global addresses, which allow us to add millions of hosts to the Internet without "real" IP addresses. This provides flexibility in our corporate networks. NAT can also allow you to use the same subnet more than once in the same network without overlapping networks.

The host on the global network before translation is considered to be an outside local host.

The command debug ip nat will show you in real time the translations occurring on your router.

The host on the private network before translation is considered to be an inside local host.

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.

The host on the private network after translation is considered to be an inside global host.

The command show ip nat translations will show you the translation table containing all the active NAT entries.

NAT is not perfect and can cause some issues in some networks, but most networks work just fine. NAT can cause delays and troubleshooting problems, and some applications just won't work.

The command ip nat pool <name> creates the pool that hosts can use to get onto the global Internet. What makes option B correct is that the range 171.16.10.65 through 171.16.10.94 includes 30 hosts, but the mask has to match 30 hosts as well, and that mask is 255.255.255.224. Option C is wrong because the pool name has a lower case "T" in the pool name. Pool name's are case sensitive.

The show ip nat statistics command displays a summary of the NAT configuration as well as counts of active translation types, hits to an existing mapping, misses (causing an attempt to create a mapping), and expired translations.