HF has highest boiling point among hydrogen halides, because it has:

Strategy: Identify compounds with similar shapes despite different central atoms.

Step 1: Isostructural Analysis

• $\ce{XeF2}$ and $\ce{IF2^-}$ (or $\ce{I3^-}$): Both are linear with 3 lone pairs on the central atom.
• $\ce{XeF4}$ and $\ce{BrF4^-}$: Both are square planar.
• $\ce{XeO3}$ and $\ce{BrO3^-}$: Both are pyramidal.

Step 2: Conclusion Identifying the pair that matches the geometry provides the answer.

$\boxed{\text{Answer: (Option) [c] [Isostructural pair]}}$