Which of the Following Statements About Internal Control Is Correct

Which of the following statements about internal control is correct?

A) The establishment and maintenance of internal control is an important responsibility of the internal auditor.
B) Properly maintained internal control reasonably ensures that collusion among employees cannot occur.
C) The cost-benefit relationship is a primary criterion that should be considered in designing internal control.
D) Exceptionally strong internal control is enough for the auditor to eliminate substantive tests on a significant account balance.