单选题：If a running process invokes the wait operation on a semaphore a

If a running process invokes the wait operation on a semaphore and cause its value to be negative, then the process will ______. @[A](1)
A. be blocked
B. change into ready state
C. continue running
D. be unblocked




A.be blocked
B.change into ready state
C.continue running
D.be unblocked


答案：A