Which of the following is not a valid IPv$6$ address?:

Group of answer choices

$2001$:$0000$:$0000$:$1234$:$4568$:$0000$:$0000$:ab

::$1$

$2001$::$12$:$0$:$0$:$1234$:$5678$

$2001$::$1234$::$56$ab:$2345$