Show abbreviations for the following addresses:

a$.0000$ : FFFF : FFFF : $0000$:$0000$:$0000$:$0000$:$0000$

b$.1234$:$2346$:$3456$:$0000$:$0000$:$0000$:$0000$: FFFF

c$.0000$:$0001$:$0000$:$0000$:$0000$: FFFF : $1200$:$1000$

d$.0000$:$0000$:$0000$:$0000$: FFFF : FFFF : $24\mathrm{.}123\mathrm{.}12\mathrm{.}6$