Where must the Wisconsin Buyers Guide be attached?

The Wisconsin Buyers Guide must be attached to the window and readable from outside the vehicle to ensure that potential buyers can easily see the information while looking at the car from the outside. This is also useful for easy reference during test drives or inspections. Option A is incorrect as it would make it difficult for potential buyers to access the information. Option C is also incorrect as it would not be visible from the outside of the vehicle. Option D is incorrect as it could obstruct the driver's view.