Level 5-2 (Mario vs. Donkey Kong: Tipping Stars)
From the Super Mario Wiki
The course has a wide and ununiform layout, comprising many Red Girder Rivets and Blue Lift Rivets. There are also several Color Switches which can be pressed to activate or disable blocks of the same color. These blocks either serve as obstructing walls or bridges between platforms. The Goal Door is located on the bottom left, under the Mini Mario's and one Mini Pauline's starting positions.
The M Coin is found on a platform towards the right side of the level, at the top. It stays behind a wall of Red Color Blocks, which should be disabled with a Red Color Switch in order to gain access to the coin.
Nintendo 3DS version
Wii U version