What is a motor cart (Motorkarren) under Austrian vehicle regulations?

1. A passenger sports car with an engine displacement of less than 1,000 cc
2. A motor vehicle designed for carrying loads or operating attachments in agriculture and forestry, with a design speed up to 50 km/h
3. An electric bicycle with pedal assistance up to 25 km/h
4. A heavy articulated lorry used for international refrigerated transit