Holding all other factors constant, which of the following factors results in an increase in sample size for substantive tests?

a. A decrease in the amount of expected misstatement in the population to be tested.

b. Stratifying the population when appropriate.

c. An increase in the amount of tolerable misstatement.

d. An increase in the desired level of assurance that the tolerable misstatement is not exceeded by the actual amount of misstatement in the population.