Which tool, service or command will enable you to learn the entire address range used by an organization or company?

A.
Traceroute

B.
Nslookup

C.
Port scanner

D.
Pingscanner

Explanation:
A ping scanner is used to do network mapping. If you are able to ping a server, you can get its IP address. With the IP address, you can ping all addresses in that IP range to discover other devices on the network, mapping the responses that are received.
Incorrect Answers:
A: The TRACEROUTE command is used to identify hops between the source and target machines. It can be used to map out the location of routers within the network.
B: The NSLOOKUP command is used to test out entries in a name server. If you can successfully imitate a secondary name server with NSLOOKUP you can initiate a Zone transfer with a Master. With a zone transfer you can identify the IP address to Name mappings of all registered nodes. The reason why this is not the answer is that NSLOOKUP only discovers registered nodes, so if the node is not in DNS, or the mapping is wrong, or the node is obsolete but not deleted, you end up with a lot of missing and inaccurate information. Usually a router is not registered in DNS, so you would not get most of the routers. Compared to either the ping scanner or port scanner, those scanners perform live polling commands against the network and identify live and operational nodes.
C: A port scanner is similar to a ping scanner in that it discovers the IP addresses, but a port scanner also discovers active ports, and is mainly used for that purpose..