Which of the following is not true about the 2-3 tree?

Which of the following is not true about the 2-3 tree?
A. all leaves are at the same level
B. it is perfectly balanced
C. postorder traversal yields elements in sorted order
D. it is B-tree of order 3

Answer:
C. postorder traversal yields elements in sorted order

Explanation:
In a 2-3 tree, leaves are at the same level. And 2-3 trees are perfectly balanced as every path from root node to the null link is of equal length. In 2-3 tree in-order traversal yields elements in sorted order.