Answer:
Preemptive multitasking is the operating system that control the processor by not involving in task cooperation and preemptive is the process of controlling the task. On the other hand, preemptive multi threading is the parallel processing system in which the execution of the thread is preemptive.
Non-preemptive multitasking is the process in which the processor are never involves with the task and it is used for many window applications. Whereas, in non preemptive multi threading when a thread are given control then, it continues run until it can control the blocks.