Under ADR 8.1.4.1(c), what minimum fire extinguisher capacity is required for a small delivery van with a maximum permissible mass of 3.0 tonnes carrying dangerous goods above 1,000 points?

1. Total minimum capacity of 12 kg dry powder
2. No fire extinguisher required for vehicles under 3.5 tonnes
3. Total minimum capacity of 8 kg dry powder, with at least one extinguisher of minimum 6 kg
4. Total minimum capacity of 4 kg dry powder, with at least one extinguisher of minimum 2 kg