Which of the following operations need to be privileged:  (Please select ALL correct answers)Group of answer choicesSet value of timerRead Clockclear memoryIssue a trap instructionturn off interruptsmodify entries in device-status tableaccess I/O device (directly)Switch from user to kernel mode

All of the operations listed need to be privileged. These operations include:

1. Set value of timer: This operation directly affects the system's scheduling and timing, which is a critical system resource. Therefore, it needs to be privileged to prevent unauthorized access.

2. Read Clock: Reading the system clock is a sensitive operation that could potentially be used for timing attacks if it were not privileged.

3. Clear memory: Clearing memory can affect the operation of other programs and the system itself, so it needs to be a privileged operation.

4. Issue a trap instruction: Trap instructions are used to interrupt the normal flow of execution, often for purposes of debugging or handling exceptions. This is a powerful operation that needs to be privileged to prevent misuse.

5. Turn off interrupts: Turning off interrupts can affect the operation of the entire system, so it needs to be a privileged operation.

6. Modify entries in device-status table: The device-status table contains critical information about the state of hardware devices. Modifying it can affect the operation of these devices, so this operation needs to be privileged.

7. Access I/O device (directly): Direct access to I/O devices can bypass the normal checks and balances provided by the operating system, so it needs to be a privileged operation.

8. Switch from user to kernel mode: This operation allows a program to gain the same level of access as the operating system itself, so it needs to be privileged to prevent unauthorized access.