单选题：Let n and m be two nodes in a binary tree. During the inorder t

Let n and m be two nodes in a binary tree. During the inorder traversal, n is visited before m provided that: @[A](3)

A. n is on the left of m
B. n is on the right of m
C. n is an ancestor of m
D. n is a descendant of m



A.n is on the left of m
B.n is on the right of m
C.n is an ancestor of m
D.n is a descendant of m


答案：A