单选题：The minimum spanning tree of any weighted graph \_\_\_\_

The minimum spanning tree of any weighted graph \_\_\_\_
@[D](3)

A. must be unique
B. must not be unique
C. exists but may not be unique
D. may not exist



A.must be unique
B.must not be unique
C.exists but may not be unique
D.may not exist


答案：D