Which of the following is a valid IPv4 address?

The correct answer, 255.255.255.0, is a valid IPv4 address because it adheres to the standards set for IPv4 addressing. An IPv4 address consists of four octets, which are decimal numbers ranging from 0 to 255, separated by dots. In this case, all four octets (255, 255, 255, and 0) fall within that valid range, making it a legitimate IP address.

Though this address is valid, it is worth noting that it is often used as a subnet mask rather than a host address in a network configuration, but it still qualifies as a valid IPv4 address.

In contrast, the other listed options contain elements that make them invalid. For instance, the address 345.0.24.6 has a value of 345 in the first octet, which exceeds the maximum allowable value of 255 for an octet. Therefore, it cannot be classified as a valid IPv4 address. The other choices, 1.1.1.1 and 54.45.43.54, are also valid IPv4 addresses as they fall within the acceptable range for each octet, but they are not the correct choice in the context