A driver holding only a Class B.1 license wants to tow a light utility trailer (acoplado) weighing 700 kg behind their car. Under the official subclass structure of the Licencia Nacional de Conducir, what applies?

1. They may tow it freely, because Class B.1 already includes trailers up to 750 kg
2. They must first obtain the Class B.2 subclass, which authorizes a B.1-type vehicle towing a trailer of up to 750 kg or a non-motorized camper, and requires 1 year of seniority in Class B.1
3. They must obtain a professional Class E.1 license, regardless of trailer weight
4. They may tow it only if the trailer carries its own insurance policy