Which of the following is not an inherent weakness in internal control? (Hint: Inherent weakness means that the issue is existing in someone or something as a permanent and inseparable element, quality, or attribute; in other words, it's not avoidable even with proper control.)

a. Collusion amongst employees

b. Improper separation of duties

c. . Management override of controls

d. All of the above are inherent weaknesses in internal control