Select the possible reason(s) when a running process has to be blocked.

There may be more than one correct answer in this question. You are required to select all correct answers (and unselect all incorrect answers) to receive full credits in this question.

1. Runtime error occurs (e.g., divide by zero) so that the process cannot continue running.

2. The required input for the process to continue running is not yet available.

3. The process has run long enough, so it voluntarily gives up the CPU to let another process run.

4. The process attempts to enter its critical region but fails since another process is in its critical region.

5. Fatal error occurs so that the process cannot continue running.

6. The process has finished its job.