Which of the following is an example of double counting in trying to compute Gross Domestic Product?
a) The sum of the total market value of steel used in producing a car and the total market value of cars m.
b) The sum of the total market value of tennis rackets and the total market value of tennis balls.
c) The sum of the total market value of salsa and the total market value of taco shells.
d) The sum of the total market value of cheese and the total market value of yoghurt.