Which of the following is NOT a correct notation for an IPv6 address?

A.
2001:0db8:0:0:0:0:1428:57ab

B.
ABCD:EF01:2345:6789:

C.
ABCD:EF01:2345:6789::1

D.
2001:DB8::8:800::417A

Explanation:
The 128 bits of an IPv6 address are represented in 8 groups of 16 bits each. Each group is written as 4
hexadecimal digits and the groups are separated by colons (:).Consecutive sections of zeroes are replaced with
a double colon (::).The double colon may only be used once in an address, as multiple use would render the
address indeterminate. The address 2001:DB8::8:800::417A uses double colon twice, which is illegal.
Incorrect Answers:
A: 2001:0db8:0:0:0:0:1428:57ab is a well-formed IPv6 address with 8 groups of 16-bit hexadecimal numbers.
B: ABCD:EF01:2345:6789:1 is a well-formed IPv6 address with 8 groups of 16-bit hexadecimal numbers.
C: ABCD:EF01:2345:6789::1 is a well-formed IPv6 address with 8 groups of 16-bit hexadecimal numbers, and
only one double colon.

https://en.wikipedia.org/wiki/IPv6