When may a Category B vehicle tow a trailer whose maximum authorised mass exceeds 750 kg?

1. Never; any trailer over 750 kg always requires Category C
2. Whenever the trailer itself does not exceed 3,500 kg, with no combination-mass cap
3. Only if type-approval rules are respected and the combination's maximum authorised mass does not exceed 4,250 kg
4. Only on motorways, and only in daylight