单选题：Given a tree of degree 3. Suppose that there are 11 leaf nodes a

Given a tree of degree 3. Suppose that there are 11 leaf nodes and 4 nodes of degree 2. Then the number of degree 3 nodes must be \_\_\_\_.


@[C](3)

A. 1
B. 2
C. 3
D. 4



A.1
B.2
C.3
D.4


答案：C