Level 4-7 (Mario vs. Donkey Kong: Tipping Stars)
From the Super Mario Wiki
The course is wide and has a number of pathways connected by Red Girders. In addition, there are several Movable Pipe outlines popping out of the ceilings and walls. The Key Mini Mario and Mini Peach start next to each other on the bottom floor, while Mini Toad is present on a ledge near them. In order to clear the level, the Key Mini Mario has to be brought to the Goal Door first to unlock it, followed by the other two Minis.
The following data applies in both the Nintendo 3DS and the Wii U versions of the game.