Which of the following is a characteristic of Class A IPv4 addresses?

Class A IPv4 addresses are characterized by their use of the range from 1 to 126. This classification was designed to accommodate a vast number of hosts on a small number of networks, making it suitable for very large organizations and service providers.

In Class A, the first octet (the first set of 8 bits) defines the network part and starts with a 0 bit, which allows for a significant amount of addresses within this class due to its large network size. This structure results in Class A supporting over 16 million hosts on each network, which is fitting for very large networks.

The other ranges listed pertain to different classes: Class B ranges from 128 to 191, which allows for a smaller number of hosts per network; Class C ranges from 192 to 223, designed for even smaller networks; and Class D is used for multicast addresses, ranging from 224 to 239. Thus, selecting the correct range of 1 to 126 effectively identifies Class A IPv4 addresses.