While inserting the elements 71, 65, 84, 69, 67, 83 in an empty binary search…

Key insight: insert each element into the BST using the rule: smaller → left, larger → right.

• Insert 71: becomes the root.

• Insert 65: 65 < 71, so 65 becomes the left child of 71.

• Insert 84: 84 > 71, so 84 becomes the right child of 71.

• Insert 69: 69 < 71 → go left to 65; 69 > 65, so 69 becomes the right child of 65.

• Insert 67: 67 < 71 → left to 65; 67 > 65 → right to 69; 67 < 69, so 67 becomes the left child of 69.

• Insert 83: 83 > 71 → right to 84; 83 < 84, so 83 becomes the left child of 84.

Final tree levels:

• Level 0: 71 (root)

• Level 1: 65 (left of 71), 84 (right of 71)

• Level 2: 69 (right of 65), 83 (left of 84)

• Level 3: 67 (left of 69)

Conclusion: 67 is at the deepest (lowest) level after all insertions, so 67 is the correct answer.