单选题：3 producers and 5 consumers share one common buffer with 7 items

3 producers and 5 consumers share one common buffer with 7 items of capacity. Please choose the initial value for a semaphore to ensure mutual exclusion. @[A](1)
A. 1
B. 3
C. 5
D. 7





A.1
B.3
C.5
D.7


答案：A