单选题：Which of the following is correct?
Which of the following is correct? @[D](1)
A. The semaphore is more powerful than the monitor.
B. The monitor is more powerful than the semaphore.
C. The critical region is more powerful than the semaphore.
D. The semaphore, the monitor, and the critical region are all powerful and equivalent to each other.
A.The semaphore is more powerful than the monitor.
B.The monitor is more powerful than the semaphore.
C.The critical region is more powerful than the semaphore.
D.The semaphore, the monitor, and the critical region are all powerful and equivalent to each other.
答案：D
A. The semaphore is more powerful than the monitor.
B. The monitor is more powerful than the semaphore.
C. The critical region is more powerful than the semaphore.
D. The semaphore, the monitor, and the critical region are all powerful and equivalent to each other.
A.The semaphore is more powerful than the monitor.
B.The monitor is more powerful than the semaphore.
C.The critical region is more powerful than the semaphore.
D.The semaphore, the monitor, and the critical region are all powerful and equivalent to each other.
答案：D