单选题：Suppose that all the leaf nodes of a given non-empty complete bi

Suppose that all the leaf nodes of a given non-empty complete binary tree $$T$$ are on the same level, and every non-leaf node has two children. If there are $$k$$ leaf nodes in $$T$$, then $$T$$ must have __ nodes in total. @[A](2)

A. $$2k-1$$
B. $$2k$$
C. $$k^2$$
D. $$2^k -1$$




A.$$2k-1$$
B.$$2k$$
C.$$k^2$$
D.$$2^k -1$$


答案：A