Which of the following is an important subjective consideration when deciding the nature of tests to use in a financial statement audit?

a. Tests of details typically provide a low level of assurance.

b. Analytical procedures are inefficient means of obtaining assurance.

c. The procedures to be applied on a particular engagement are a matter of the auditor's professional judgment.

d. The use of tests of controls should be considered without regard to the level of assurance required.