Explanation:

When an interrupt occurs, the operating system needs to handle it appropriately to ensure the smooth functioning of the system. The correct answer is option 'D' because the operating system may change the state of the interrupted process to blocked and schedule another process. Let's understand this in detail:

Interrupts:
Interrupts are signals sent to the processor from either hardware devices or software exceptions. They are used to indicate events that require immediate attention from the operating system. When an interrupt occurs, the processor temporarily stops executing the current process and transfers control to a specific interrupt handler routine.

Handling Interrupts:
When an interrupt occurs, the operating system follows a specific sequence of steps to handle it:

1. Saving the state: The operating system saves the current state of the interrupted process, including the program counter, registers, and other relevant information. This allows the system to resume the interrupted process later.

2. Interrupt Service Routine (ISR): The operating system then executes the Interrupt Service Routine (ISR) associated with the interrupt. The ISR is a predefined routine that handles the specific interrupt. It performs the necessary actions to process the interrupt and fulfill its requirements.

3. Interrupt Priority: Depending on the interrupt priority and the system's configuration, the operating system may decide to change the state of the interrupted process to blocked. This means that the process is temporarily suspended and cannot execute until the interrupt is fully handled. The operating system may schedule another process to run while the interrupted process is blocked.

4. Scheduling and Resuming: After processing the interrupt, the operating system may choose to resume the execution of the interrupted process. It restores the saved state of the process and continues its execution from where it left off. Alternatively, the operating system may decide to prioritize other processes based on their scheduling policies and the importance of the interrupted process.

Conclusion:
In summary, when an interrupt occurs, the operating system may change the state of the interrupted process to blocked and schedule another process. The exact behavior depends on the interrupt priority, the system's configuration, and the scheduling policies implemented by the operating system. Interrupt handling is essential for managing various events and ensuring the efficient operation of the system.