A /8 CIDR notation can also represent a Class A address.

• A. Class B Address
• B. Class A Address
• C. Class C Address
• D. Class D Address

Answer: (B)

A /8 CIDR notation means the network portion is defined by the first eight bits, i.e., the entire first octet, while the remaining three octets identify hosts within that network. This aligns with how Class A networks were defined in the old classful addressing scheme, where the default subnet mask is 255.0.0.0, or /8 in CIDR terms. So a block like x.y.z.w with a /8 mask uses the first octet to determine the network, which is exactly how Class A addresses work.

For example, 10.0.0.0/8 represents the Class A space from 10.0.0.0 to 10.255.255.255. In contrast, Class B uses a /16 mask (255.255.0.0) and Class C uses a /24 mask (255.255.255.0). Class D is multicast and isn’t addressed in the same unicast host-network way.