$4.$ When the computed upper exception rate is greater than the tolerable exception rate, it is necessary for the auditor to take specific action. Which of the following courses of action would be most difficult to defend if the auditor is ever subject to review by a court?a$.$ Change the tolerable exception rate so as to accept the sample results.b$.$ Expand the sample size and perform more tests.c$.$ Revise the assessed control risk.$)$ d$.$ Write a letter to management which outlines the control deficiencies.