As defined by the original Internet Protocol standard, which of the following choices identifies the three classes of IP addresses used for networks and what differentiates them?

Class A$,$ B$,$ C$,$ differing by the number in the first byte

Class A$,$ B$,$ C$,$ differing by how many bits distinguish the networks from the hosts

Class $1,2,3,$ differing by how many bits distinguish the networks from the hosts

Class $1,2,3,$ differing by the number in the first byte