initial
Will you have more than 5 passengers?
bus_state carry_state
carry_state
Do you need to cary a lot of stuff?
suv_state size_state
size_state
Do you want a big car?
speed_state vwb_state
speed_state
Do you want a fast car?

bus_state
I suggest a bus.

suv_state
I sugest a SUV.

vwb_state
I suggest a VW Beetle