Option D Should be Correct.
A wait state is a delay experienced by a computer processor when accessing external memory or another device that is slow to respond. Each of the cycles spent waiting is called a wait state. Wait states are a pure waste of a processor's performance
Wait states are a pure waste of a processor's performance. Modern designs try to eliminate or hide them using a variety of techniques: CPU cache, instruction pipelining, instruction pre fetch , branch prediction, simultaneous multithreading and others. No single technique is 100% successful, but together can significantly reduce the problem.
