One control objective for an operating system is that it must be protected from itself. Which of the following statements best explains this concept? Select one: a. The operating system must be able to prevent unauthorized users from accessing, corrupting, or destroying other users' data. O b. User applications must not be allowed to gain control of or damage the operating system. 0 c. No operating system module should be allowed to corrupt or destroy another operating system module. O d. The operating system should be able to gracefully terminate activities, and later recover to its previous state. Reconciliation of cash accounts may be referred to as what type of control? Select one: a. Preventive. b. Non-routine. c. Detective. d. Adjustive