Which compound from following contains iodine with highest oxidation number ?

Which compound from following contains iodine with highest oxidation number ?
  1. $\mathrm{KIO}_3$
  2. KI
  3. $\mathrm{IF}_5$
  4. $\mathrm{KIO}_4$

Asked in: MHT CET 2024 (04 May Shift 1)

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