Consider the following reaction sequence The correct statements about $Z$ are I. It gives yellow precipitate with $\mathrm{I}_2$ and NaOH solution. II. It undergoes disproportionation reaction in the presence of concentrated NaOH solution. III. It undergoes Wolff-Kishner reduction. IV, If forms red precipitate with Fehling's reagent.

Identify $A$ and $B$ from the following reactions