Option b is the correct answer for the above question.
Explanation:
Thrashing occurs when the virtual memory of the computer is more used. It is because the system does not have more memory. That's why the virtual memory is busy in the paging or other work of the operating system and there is no memory left for the other useful work of the system and then Thrashing occurs.
The question statement states the same which is described above and this is the cause when thrashing occurs. Hence the b option is correct. while other is not because--
Option "a" states about spooling but spooling is a concept of copy the data.
Option C states about an interrupt but it is a concept to stop the work of CPU when any input is coming from the outside.
Option D states about a pooling signal which is an operation of computers.
