Petrol, diesel, electric, hybrid and gas
Petrol: high power density, but exhaust with CO₂, nitrogen oxides and particulates. Diesel: even more energy per litre, but heavy particulate emissions if the filter is worn. EV: zero tailpipe emissions where you drive, but cold weather can cut range by 20–30 percent. Hybrid: combines electric at low speed with combustion at highway speed. Biogas and E85: low climate impact when sustainably produced. Range, infrastructure and charging time differ drastically between them.
No fuel is without trade-offs. The exam wants you to weigh climate impact, emissions, range, infrastructure and cost against each other. The right choice depends on how the car is used — short commutes, long trips or hauling.