Must an EX/II or EX/III vehicle carrying Class 1 explosives carry portable fire extinguishers, and if so, what size?

1. No, fire extinguishers are prohibited because water causes explosions
2. Yes, at least two portable fire extinguishers (e.g. 2 kg cab unit plus 6 kg dry powder unit depending on vehicle mass)
3. Only a 500 ml plastic water spray bottle is required
4. Extinguishers are required only when driving through subsea tunnels