单选题：For a binary tree, its pre-order traversal sequence is `1 2 3 4

For a binary tree, its pre-order traversal sequence is `1 2 3 4 5`, and its post-order traversal sequence is `5 4 3 2 1`. Which of the following statements about the tree is true? @[C](2)

A. Its height can be 4.
B. The number of its possible shapes is 8.
C. It has only one leaf node.
D. It cannot be a binary search tree.




A.Its height can be 4.
B.The number of its possible shapes is 8.
C.It has only one leaf node.
D.It cannot be a binary search tree.


答案：C