Assume your car has an enclosed chassis structure. What is true about holes?

1. You are not allowed to have holes in the chassis structure
2. You are not allowed to have holes in the chassis structure, other than a maintenance hole to adjust the brake pedals
3. You must have at least one hole of 10mm in diameter to vent the chassis structure, in case of any accumulation of gasses
4. You must have at least two holes of 25mm to vent the chassis structure, in case of any accumulation of liquidsCorrect