According to COSO, which of the following issues should lead to the greatest concern regarding the effectiveness of an entity's system of internal control?

A$.$

Errors from control failures that were not detected timely by the routine monitoring procedures.

B$.$

Additional evaluations solely to meet regulatory requirements when elements of other procedures would be sufficient.

C$.$

Unwarranted duplication of efforts when multiple people monitor the same control.

D$.$

Monitoring internal control in areas that have never had a control failure.