The correct option is B Bicycle
Air is said to be polluted when there is any change in the normal amount of any of the components of air or when foreign substances mix with air.
Burning of fossil fuels, smoke from industries, burning of wastes like plastics, etc. are the factors responsible for air pollution.
We can control air pollution by not burning wastes and fossil fuels, by using electric cars, bicycles or by using public transport.
Out of the given options, a bicycle will be the best choice since it does use any fuel while all other vehicles here use fossil fuels.