Which of the following options lists IPv4 private address ranges commonly used in LANs?

• A. 192.168.0.0/16, 10.0.0.0/8, 172.16.0.0/12
• B. 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
• C. 172.16.0.0/12, 192.168.1.0/24, 10.0.0.0/8
• D. 10.0.0.0/8, 172.32.0.0/12, 192.168.0.0/16

Answer: (B)

Private IPv4 addresses are reserved for use inside local networks and are not routable on the public Internet. They let LANs assign addresses without consuming public space, often behind a NAT device that translates to a public address when accessing the Internet.

The standard private blocks are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Together they cover large, commonly used address ranges for internal networks:

• 10.0.0.0/8 spans from 10.0.0.0 to 10.255.255.255

• 172.16.0.0/12 spans from 172.16.0.0 to 172.31.255.255

• 192.168.0.0/16 spans from 192.168.0.0 to 192.168.255.255

The best option lists all three canonical private blocks, which is why it’s the correct choice. Other options either include a non-private range (such as 172.32.0.0/12) or specify only a subset of a private block (like 192.168.1.0/24) rather than the full private ranges used in LANs.