“B” ?!? What the hell is ‘B’?!
“It get 300 Hectares per liter of kerosene. Put it in ‘H’!”
From what I could find, apparently some sort of engine braking mode.
B is breaking mode. The car does does not have discrete gears, so there is no low gears such as 1 and 2 to shift into. You use B for engine breaking on long downhills for example. The car uses a type of Continuously Variable Transmission.
Well, I’ll be sure to stay out of B, then. 
Braking. BRAKING.