Which statement best describes IPv4 and IPv6 addressing basics?

• A. IPv4 uses 32-bit addresses with decimal dotted notation; IPv6 uses 128-bit addresses with hex.
• B. IPv4 uses 128-bit addresses; IPv6 uses 32-bit addresses.
• C. IPv4 addresses are in binary; IPv6 addresses are decimal.
• D. IPv4 and IPv6 use the same address length.

Answer: (A)

IPv4 and IPv6 addressing differ mainly in address length and how they’re written. IPv4 uses 32-bit addresses and is typically shown in decimal dotted notation (for example, 192.168.0.1), which is easy to read for humans but represents a 32-bit binary value. IPv6 uses 128-bit addresses and uses hexadecimal notation separated by colons (for example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334). In practice, the IPv6 representation is often compressed to shorten runs of zeros, but it’s still hex-based and 128 bits long. This is why the statement is correct: it accurately describes the length and the numeral system used for each protocol. The other statements misstate either the address length or the way addresses are presented—IPv4 isn’t 128 bits and IPv6 isn’t decimal, and they don’t use the same address length.