单选题：The mutual exclusion semaphore of two concurrent processes has t
The mutual exclusion semaphore of two concurrent processes has the value 0 (zero) at this moment. It indicates that ____________.@[B](1)
A. no process has entered the critical-section
B. a process has entered the critical-section, and no process is being blocked
C. a process has entered the critical-section, another process is waiting to enter the critical-section
D. two processes have entered the critical-section
A.no process has entered the critical-section
B.a process has entered the critical-section, and no process is being blocked
C.a process has entered the critical-section, another process is waiting to enter the critical-section
D.two processes have entered the critical-section
答案：B
A. no process has entered the critical-section
B. a process has entered the critical-section, and no process is being blocked
C. a process has entered the critical-section, another process is waiting to enter the critical-section
D. two processes have entered the critical-section
A.no process has entered the critical-section
B.a process has entered the critical-section, and no process is being blocked
C.a process has entered the critical-section, another process is waiting to enter the critical-section
D.two processes have entered the critical-section
答案：B