None of the above: all those bio-ethanols are running up food inflation rates, and will have to be abadonned.
THE REAL SOLUTION!!!!
Remember that you've read here first.
The solution will be the car that runs on compressed air
Held in big 300 l tanks and 300 bar, there won't be anymore explosion or fumesor even excessive heat.
picture your Once the piston is above, you inject 300 bar air and the detention of the gas to 1 or 2 bar will push the cylinder down. No explosion, just a gas gaining back its proper state, and even provoking some cooling (rather than heating), probably causing some condension on the engine surface.
A french manufacturer has those vehicles close to join the marke^place and the car have autonomy of km (better than electric, which take up hours to recharge the batteries)).
Tank stations you ask?: place every ten Km a windmikll (the most powerful can develop up to 2 MW) to drive a HP compressor to fill up a tank of the station (in case of prolonged lack of wind, the compressor can work on electricuty as well): >>> the driver comes up to the tank and connects to his empty car tanks the hoses between the two, opens the valves and within 20 seconds, his car tanks are filled again....
No explosion, flame or fume. no air pollution both in driving around and producing the "fuel", this is almost like a miracle..... And it's about to happen (I'm fighting for it), too!!!
Compressed air is cheap and can be compressed cleanly (but must be filtered from water, oil and dust before reaching the "combustion chamber"
The big downside: if car makers don't lose jobs, anyone owning a compressor can have undefined access to an unlimited source of energy (ths isan enormous plus for you and I), which NOBODY amongst politicians and economists want >> too much loses in revenues. and a whole side of petro-industries becoming almost useless.