In a binary search tree, what invariant must hold for every node?

In a binary search tree, what invariant must hold for every node?

• A. Left subtree values are greater; right subtree values are less.
• B. All nodes in left subtree are greater than all nodes in right subtree.
• C. Left subtree values are less than the node, right subtree values are greater.
• D. Left subtree values are less than the node, right subtree values are greater.

Answer: (D)