What control and service work has to be carried out regularly on a fifth wheel?

The selected combination is correct because regular maintenance of a fifth wheel is crucial for safe operation. Lubricating the fifth wheel helps reduce friction and wear, ensuring smooth maneuverability. Checking the fixing to the frame ensures that the fifth wheel is securely attached, which is essential for the stability and safety of the trailer while driving. These practices are aligned with German traffic regulations, which emphasize the importance of vehicle maintenance to prevent accidents and ensure safety on the road. Regular checks and maintenance help identify issues before they lead to failure, thereby supporting safe driving standards.