The correct option is B driving vehicles at a moderate speed
It is important to save the existing reserves of fossil fuels before they exhaust for future generations. Few ways to save fossil fuels in day to day activites are:
∙ switching off the engines of the vehiles while waiting or at traffic lights
∙ driving vehicles at moderate speed as far as possible to reduce unnecessary usage of petrol/diesel
∙ using natural gas instead of petrol in vehicle as natural gas is a cleaner fuel and reduce pollution
∙ using LPG for cooking as it is eco-friendly