In a Class A Internet address, which of the following network numbers are reserved?

In the context of Class A Internet addresses, certain network numbers are reserved for specific purposes. The number 0 is reserved for use as a "default route" or to denote hosts on the same network. It is not designated for any specific network and typically signifies an unspecified or wild card address in routing protocols.

The number 127 is specifically reserved for loopback addresses, which are used for testing and diagnostics on the local machine. Any address in the range 127.0.0.0 to 127.255.255.255 allows a host to communicate with itself for purposes such as validating the network stack or troubleshooting. This loopback feature is key in network operations and software development.

The combination of both numbers being reserved for these important functions in networking illustrates why the choice indicating that both 0 and 127 are reserved is correct. Option 255 does not carry any special reserved status in the context of Class A addressing and is typically used as a broadcast address in some limited environments, making those options irrelevant for this specific question regarding reserved addresses.