$(6$pts$,2$ pts each$)$ Expand these IPv$6$ addresses to their unabbreviated form. I will subtract $1$pt

if any leading zeros are missing.

a$.2001$:$428$:$0$:$0$:$16$:$155$::$0$

b$.0$:$2$:$1$::$220$:$1$:$0$

c$.0$:$0$:AOB:$0$:$0$:FF::$0$