What is the CPU utilization of a system with a degree of multiprogramming equals $4$ if the probability of a process in the waiting state is $0\mathrm{.}5?$

A$.$ about $64\%$

B$.$ about $74\%$

C$.$ about $84\%$

D$.$ about $94\%$

E$.$ about $99\mathrm{.}9\%$