Answer : 3. "128 bits"
Explanation :

Answer: C) 128 bits Explanation: IPv6 - Internet Protocol Version 6. IPv6 addresses have a size of 128 bits. Internet Protocol Version 6 [IPv6] is the successor to the Internet's first addressing infrastructure, Internet Protocol version 4 (IPv4). In contrast to IPv4, which defined an IP address as a 32-bit value, IPv6 address have a size of 128 bits.