Which of the following is most likely to be the reason for auditors to use a simulation model instead of an analytical model to assist them to evaluate how well a system safeguards assets or maintains data integrity?

a. Simulation models are cheaper to design, implement, and execute

b. The analytical model needed is not mathematically tractable

c. Evaluation costs are reduced over a wide range of values of the independent variable and changes in the structure of the model

d. A simulation model allows the mean and variance of the probability distribution associated with the reliability of the internal control system to be calculated