What preventive maintenance can you carry out on the battery?

The combination of options 1 and 2 is correct because checking cable connections and battery support ensures that the battery is securely mounted and won't cause electrical issues while driving. Cleaning and greasing the poles prevents corrosion, which can affect the battery's performance and longevity. These maintenance tasks are important for vehicle safety and reliability, which are emphasized in German traffic regulations that mandate regular vehicle inspections and maintenance to ensure roadworthiness. Option 3, exchanging battery acid, is not typically a regular maintenance task for vehicle owners and is not necessary unless specific issues arise with the battery. Thus, focusing on the first two options helps maintain optimal battery function and compliance with safety regulations.