单选题：If following situation appears in the resource-allocation graph,

If following situation appears in the resource-allocation graph, then we can consider that system is in deadlock state。@[C](1)
A. there is a loop
B. there is not any loop
C. each resource has only one instance and there is a loop
D. there is at least one request edge for each process node




A.there is a loop
B.there is not any loop
C.each resource has only one instance and there is a loop
D.there is at least one request edge for each process node


答案：C