Step 1: Idea:
Test for the structural unit that leads to the $\text{CI}_3\text{-C=O}$ intermediate.
Step 2: Result:
Options A, B and C each have the methyl-carbonyl or methyl-carbinol unit. Isobutyl alcohol has $\text{-CH}_2\text{OH}$ at the end of a branched chain. Oxidation gives an aldehyde with no $\text{CH}_3\text{CO-}$ group.
Final Answer:
Isobutyl alcohol cannot form iodoform, option (D).
\[ \boxed{\text{Isobutyl alcohol}} \]