Explanation
Why Correct: West Bengal shares a 664 km boundary with Bihar, which is longer than its boundaries with Jharkhand (500 km), Odisha (480 km), and Assam (267 km).
Distractor Analysis: Jharkhand shares a 500 km boundary with West Bengal after its creation from Bihar in 2000. Odisha (formerly Orissa) shares a 480 km boundary with West Bengal. Assam shares a 267 km boundary with West Bengal, primarily in the northern region.
Takeaway: West Bengal shares international boundaries with Bangladesh (2,217 km), Nepal (99 km), and Bhutan (183 km), making it the only Indian state with three international borders.