Easy... you need to go to 1 player - Time trials and race against ghosts. Once you beat a fair number of them, you'll get staff ghosts. Once you beat a fair number of those, you get your outfit.
There isn't a Mii Outfit C.
you can't get clothes you can choose the colour of your shirt though (or dress)
Mii Outfit C doesn't exist.
If you have a red outfit and you have Mii out fit B the outfit will be just like Mario's outfit.
You can't unlock Mii outfit C.
there is no mii outfit c.
mii outfit c does not exist
Mii outfit A looks like a jump suit. Mii outfit B looks like Mario or Luigi's outfit.
No there is only a mii outfit a and b.
Your mii can have two outfits-outfit A is fairly easy to unlock but outfit B is harder. Mii (Outfit A) - Win 100cc Special Cup Mii (Outfit B) - Unlock all Expert Staff Ghosts in all 32 Courses
Mii outfit C is not real. So, obviously, you can't unlock it.
Sorry, no. Theres only Mii outfit A and B.