单选题：Given a tree of degree 6. Suppose that the numbers of nodes of d

Given a tree of degree 6. Suppose that the numbers of nodes of degrees 1, 2, 3, 4, 5, 6 are 3, 5, 3, 4, 2, 1, respectively. Then the number of leaf nodes must be: @[D](3)

A. 35
B. 31
C. 33
D. 37



A.35
B.31
C.33
D.37


答案：D