Suppose that a firm has historically been achieving "Three Sigma" quality. If the firm later changes its quality management practices such that it begins to achieve "Six Sigma" quality, which of the following phenomena will result?

a. The average number of defects will be cut in half.
b. The specification limits will be moved twice as far from the mean.
c. The average number of defects will be cut by 99.9997%.
d. The average number of defects will be cut by 99.87%.
e. The average number of defects will be cut by 99.73%.