Which of the following tree data structures is not a balanced binary tree?

Correct Answer (Detailed Explanation is Below)

A. B-tree

Detailed Explanation

✅ (b) AVL Tree

• It is a self-balancing binary search tree.

• Height difference between left and right subtree ≤ 1.

• Always balanced.

✅ (c) Red-Black Tree

• Also a self-balancing binary search tree.

• Maintains balance using color properties.

✅ (a) Splay Tree

• It is a self-adjusting binary search tree.

• After every operation, accessed node is moved to root.

• It does not guarantee strict balance at all times, but it is still a binary tree.

❌ (d) B-Tree

• It is not a binary tree.

• Each node can have more than two children.

• Therefore, it is not a balanced binary tree.