You have to change the front-right wheel of your biaxial motor vehicle. You apply a wheel chock to prevent the vehicle from accidentally rolling off. What must you be aware of when doing so?

The combination of options 1 and 2 is essential for safely changing a wheel.

Option 1 states that the motor vehicle should be on the most stable ground possible, which is crucial to prevent any accidental rolling while you are working on it. A flat and stable surface ensures that the vehicle remains secure while you apply a wheel chock.

Option 2 emphasizes the importance of having a wheel on the rear axle. When you apply a wheel chock to a rear wheel, it adds an additional layer of safety by preventing the vehicle from moving forward or backward during maintenance.

Option 3 is less relevant in this specific situation, as it does not contribute to the safety measures required when changing a front wheel.

In summary, selecting options 1 and 2 reflects a proper understanding of the necessary precautions to safely perform this task under German traffic rules. It highlights the importance of maintaining stability and using proper equipment to ensure both safety and compliance with regulations.