The major product in the following transformation is

The major product of the following reaction is

Arrange the following in decreasing order of electrophilicity of carbonyl carbon.

Consider the following reaction sequence:
$\text{But-2-ene}$ $\xrightarrow{\text{ozonolysis}} X$ $\xrightarrow[(ii) H_3O^+]{(i) CH_3MgBr} Y$ $\xrightarrow[573 \ K]{Cu} Z$
The correct statements about $Z$ are:
$I$. It gives yellow precipitate with $I_2$ and $NaOH$ solution.
$II$. It undergoes disproportionation reaction in the presence of concentrated $NaOH$ solution.
$III$. It undergoes Wolff-Kishner reduction.
$IV$. It forms red precipitate with Fehling's reagent.

$CH_3-CH(OH)-CH_3 \xrightarrow{Cu/300^\circ C} \text{Product (X)}$. Which of the following is correct about product $X$?

Compound '$A$' (molecular formula $C_3H_8O$) is treated with acidified potassium dichromate to form a product '$B$' (molecular formula $C_3H_6O$). '$B$' forms a shining silver mirror on warming with ammoniacal silver nitrate. '$B$' when treated with an aqueous solution of $H_2NCONHNH_2 \cdot HCl$ and sodium acetate gives a product '$C$'. Identify the structure of '$C$.