Complete combustion occurs when a fuel burns completely with oxygen, producing primarily carbon dioxide and water. For internal combustion engines, this requires a specific mixture of air and fuel.
The ideal ratio of air to fuel required for complete combustion is called the stoichiometric ratio. For gasoline (petrol) in typical internal combustion engines, this ratio is approximately 14.7:1 by mass. This means about 14.7 parts of air are needed for every 1 part of fuel.
Comparing the theoretical value of 14.7:1 with the given options:
The value 14.6 is the closest to the standard stoichiometric air-to-fuel ratio for complete combustion in internal combustion engines.