Which of the following is/are correct inorder traversal sequence(s) of binary search tree(s)? I. $3, 5, 7, 8, 15, 19, 25$ II. $5, 8, 9, 12, 10, 15, 25$ III. $2, 7, 10, 8, 14, 16, 20$ IV. $4, 6, 7, 9, 18, 20, 25$

A fundamental property of a Binary Search Tree (BST) is that its inorder traversal always visits the nodes in strictly non-decreasing (sorted) order.

Let us check each sequence:

• I. $3, 5, 7, 8, 15, 19, 25$ is strictly in ascending order $\implies$ Valid inorder sequence.

• II. $5, 8, 9, 12, 10, 15, 25$ is not sorted because $12 > 10$ $\implies$ Invalid.

• III. $2, 7, 10, 8, 14, 16, 20$ is not sorted because $10 > 8$ $\implies$ Invalid.

• IV. $4, 6, 7, 9, 18, 20, 25$ is strictly in ascending order $\implies$ Valid inorder sequence.

Therefore, only I and IV are correct inorder traversal sequences.

Hence, (A) is the correct option.