First WiiU game to reach 5 million in sales?

[OverseasJet]

I know for sure that NSMBU and MK8 will be the first Wii U games to hit that 5M mark. I think NSMBU will get there first though due to the bundles but I feel as if MK8 will surpass NSMBU eventually as the top selling Wii U game. I'm sure MK8 will be heavily bundles in the future as well though.