Your vehicle’s brake light is not working. What is the right course of action?

You chose both answers 1 and 2, which is correct. If your vehicle’s brake light is not working, you need to ensure it gets fixed before driving further. You are allowed to either have the repair done by a professional garage or determine and repair the fault yourself if you are able. Both methods are acceptable as long as the brake light is made to work again. However, simply arranging for the brake fluid to be changed is not related to fixing a faulty brake light, so only answers 1 and 2 are correct. For the German driving test and on the road, the key rule is: any lighting defect, especially safety-related ones like brake lights, must be fixed immediately—either by a professional or by yourself if you're competent.