Which address format is used to specify IPv6 addresses?

The correct answer is that IPv6 addresses are specified in hexadecimal format. IPv6 addresses are composed of 128 bits, and to make them more human-readable, they are represented as eight groups of four hexadecimal digits, separated by colons.

Hexadecimal is particularly useful here because it can compactly represent binary data: each hexadecimal digit corresponds to four bits. This allows the lengthy binary sequence of an IPv6 address to be shortened significantly, making it easier for users to read and write.

Alternatively, the other address formats are less suitable for IPv6 representation. For example, binary is not typically used because it would be cumbersome for users to work with long strings of ones and zeros. Decimal is exclusively used for IPv4 addresses and is not applicable to IPv6. Octal format, which represents values in base eight, is not used in IP addressing at all, further highlighting why hexadecimal is the appropriate choice for IPv6.