Iodoform test producing yellow CHI3 and specific carboxylate

Steps:

• Identify the reaction as iodoform test with I2(aq) in alkali for compounds containing CH3C(O)- or CH3CH(OH)- groups.
• The test yields yellow CHI3 precipitate and RCO2- from R C(O) CH3.
• Match CH3CO2- to R = CH3, requiring W = CH3C(O)CH3 (propanone).
• Precipitate is CHI3, not CH3I (methyl iodide, colorless liquid, no ppt).

Not enough information: Choices B–D identical (propanone, CH3I); A differs but CH3I mismatches yellow ppt; ambiguous without clarified options.

Final answer: Not enough information.