Correct Answer - Option 3 : The executing thread is never interrupted
A preemptive kernel is where the kernel allows a process to be removed and replaced while it is running in kernel mode.
Preemptive scheduling occurs When a process switches from the running state to the ready state (for example, when an interrupt occurs,it have high priority) OR When a process switches from the waiting state to the ready state (for example, at the completion of I/O) or when a special demand occurs from resource side.
So in preemptive kernel executing thread can be interrupted.
Non preemptive kernel:
It does not allow a process running in kernel mode to be preempted; a kernel-mode process will run until it exits kernel mode, blocks, or voluntarily yields control of the CPU.
Under non-preemptive scheduling, once the CPU has been allocated to a process, the process keeps the CPU until it releases the CPU either by terminating or by switching to the waiting state.