Which trailers may a Category F holder tow behind a self-propelled working machine (selbstfahrende Arbeitsmaschine) or a Sonderkraftfahrzeug?

1. All trailers, with no mass restriction at all
2. Only light trailers up to 750 kg highest authorised mass
3. Trailers with a highest authorised mass of not more than 3,500 kg
4. No trailers may be towed behind these vehicles