With these licenses you may drive with a trailer whose maximum permissible mass does not exceed 750 kilograms, while a heavier one, as a rule, needs an additional category, for example “BE” or “CE”.
Under the Law on Ensuring Road Traffic Safety (article 27), persons holding a driver's license for categories “B”, “C”, “D” or subcategories “C1”, “D1” may drive their vehicles with a trailer whose maximum permissible mass does not exceed 750 kg. Towing a heavier trailer, as a rule, needs an additional category: only with category “B” is a trailer heavier than 750 kg allowed, if its maximum permissible mass does not exceed the car's unladen mass, and the combination's does not exceed 3500 kg.
Option 1. The common limit for all these categories and subcategories is 750 kg, not 950 kg.
Option 2. The law limits the trailer's maximum permissible mass to 750 kg, so 850 kg is wrong.