Under GB 7258-2017, how many operational fire extinguishers must a large passenger bus (length $\ge 9$ meters) carry at a minimum, and where should they be located?

1. At least two certified ABC dry powder or water-based fire extinguishers (each $\ge 2$ kg or $\ge 3$ L), with at least one located near the driver seat and one located in the passenger cabin / rear exit area
2. Only one small aerosol can placed in the luggage trunk
3. No fire extinguishers are required if the bus has an automatic engine system
4. Ten extinguishers placed exclusively on the vehicle roof