Name the private IPv4 address ranges for Class A, Class B, and Class C networks.

• A. Class A private: 10.0.0.0–10.255.255.255; Class B private: 172.16.0.0–172.31.255.255; Class C private: 192.168.0.0–192.168.255.255.
• B. Class A private: 10.0.0.0–10.0.0.255; Class B private: 172.16.0.0–172.31.255.255; Class C private: 192.0.0.0–192.0.0.255.
• C. Class A private: 10.0.0.0–10.255.0.0; Class B private: 172.0.0.0–172.15.255.255; Class C private: 192.168.0.0–192.168.255.255.
• D. Class A private: 10.0.0.0–10.255.255.255; Class B private: 172.16.0.0–172.31.255.255; Class C private: 192.0.0.0–192.0.0.0.

Answer: (A)

Private IPv4 address ranges are set aside for use inside local networks and are not routable on the public Internet. They come from RFC 1918 to let organizations address internal devices without wasting public addresses, with Network Address Translation (NAT) used to reach the Internet.

The correct private ranges are:

• Class A private: 10.0.0.0 through 10.255.255.255 (the entire 10.0.0.0/8 block)

• Class B private: 172.16.0.0 through 172.31.255.255 (the 172.16.0.0/12 block)

• Class C private: 192.168.0.0 through 192.168.255.255 (the 192.168.0.0/16 block)

These blocks are chosen to support networks of different sizes: a large 10.x network, a medium 172.16–172.31 range, and smaller 192.168 networks commonly used in home and small office setups. Other options mix incorrect boundaries or include non-private ranges (for example, ranges that don’t cover the full /8, /12, or /16 blocks, or use 192.0.0.0, which is not private).