Which of the following addresses does not represent an IPv4 address?

An IPv4 address is composed of four octets, each ranging from 0 to 255, and separated by periods. In the provided answer, the choice representing 256.100.50.25 is not valid because the first octet exceeds the maximum limit of 255, which disqualifies it from being recognized as a proper IPv4 address.

The other options provided all consist of octets that fall within the acceptable range. For instance, 192.168.1.1, 10.0.0.1, and 172.16.0.5 are all valid IPv4 addresses, as each octet lies between 0 and 255. This fundamental understanding of the structure of IPv4 addresses is crucial for distinguishing between valid and invalid IP addresses.