You take over a semitrailer which you have not used before. What must you remember before attaching the semitrailer?

Your selected combination is correct because both points emphasize crucial safety aspects of attaching a semitrailer.

Checking the coupling pin for wear or damage is essential to ensure that the connection between the truck and the semitrailer is secure, which is legally required under German road traffic regulations for ensuring safe towing.

Ensuring adequate space between the driver's cabin and the semitrailer is also vital for maneuverability and driver safety. This space helps prevent collisions and allows for safe navigation, especially when turning or changing lanes.

While the size of the tyres is important for performance and safety, the first two points directly relate to securing the trailer properly and maintaining safe handling, which is why they are prioritized in the correct answer. It's important to consider all relevant factors to maintain safety on the roads and comply with regulations.