Please answer with reason for all why the option is correct and why the other options are incorrect

Please do not touch this question if you are going to provide useless explanation

I will rate the answer

Which substantive approach is likely the most appropriate to be performed over management's estimate of pre-tax income projections?

A. Test the mathematical accuracy of the projections and rely on controls to obtain comfort over the completeness and accuracy of projections

B. Test the data used about past and current conditions that were used in the development of the projections

C. Test the assumptions used in the projections in order to validate accuracy of the model

D. Test the data, assumptions and model used by management in developing its projections