[单选题]What's the difference between a binary search tree and a regular binary tree? 二叉搜索树之区别于普通的二叉树在于：cr4答案窝(daanwo.com)-大学生作业答案及考资分享平台
AEach node is less than or equal to the nodes in its right sub-tree, while being greater than or equal to the nodes in its left sub-tree. 任意节点均不大于其右子树中的节点，不小于其左子树中的节点cr4答案窝(daanwo.com)-大学生作业答案及考资分享平台
BEach node is less than or equal to its right child, while being greater than or equal to its left child 任意节点均不大于其右孩子，不小于其左孩子cr4答案窝(daanwo.com)-大学生作业答案及考资分享平台
CEach node (except the root) is less than or equal to its parent 除了根节点外所有节点均不大于其父亲cr4答案窝(daanwo.com)-大学生作业答案及考资分享平台
DThe keys are comparable 关键码可以比较