单选题：One semaphore variable mutex is used by two concurrent processes

One semaphore variable mutex is used by two concurrent processes for mutual exclusion access to one common variable. If mutex = 1, then it indicates that ______. @[A](1)
A. no process is in the critical section.
B. one process is in the critical section and the other is waiting for entering the critical section.
C. one process is in the critical section and the other is not waiting for entering the critical section.
D. two processes are in the critical section.




A.no process is in the critical section.
B.one process is in the critical section and the other is waiting for entering the critical section.
C.one process is in the critical section and the other is not waiting for entering the critical section.
D.two processes are in the critical section.


答案：A