How do you get the last cart in Mario cart wii?

To unlock the last kart in Mario Kart Wii, you need to achieve a specific accomplishment: you must win all 150cc cups, including the Special Cup. After completing this challenge, the "Mii" character's special kart, known as the "Mii Outfit B," will become available to you. Make sure to play through all the cups and consistently perform well to secure first place in each race.