Solution

The correct answer is 2) B, C Only.

Key Points

• Statement B: In a complete binary tree, with i internal vertices, it has i + 1 leaves. This is true because in a complete binary tree, every internal node has exactly two children. Therefore, if there are i internal nodes, there will be i + 1 leaves.
• Statement C: In a complete binary tree, with ℓ leaves it has ℓ - 1 internal vertices. This is true because in a complete binary tree, the number of internal vertices is always one less than the number of leaves.

Additional Information

• Statement A: It has always odd number of vertices. This is incorrect. A complete binary tree can have an odd or even number of vertices.
• Statement D: With 2n - 1 vertices, it has n leaves. This is incorrect. The correct relationship between the number of vertices and leaves in a complete binary tree does not follow this formula.