What must you do when leaving your car?

Your answer is correct because these steps are essential for safety when leaving your car according to German traffic rules. First, looking out for traffic behind before opening the door prevents accidents with passing vehicles or cyclists. Second, securing the vehicle against rolling away, such as by applying the handbrake or putting the car in gear, ensures it does not move unintentionally and cause harm or damage. Third, securing the vehicle against unauthorized use, like locking the doors, helps prevent theft or unauthorized driving. Following all these steps helps protect yourself, other road users, and your property.