Which of the following is obtained as a product when ethylene reacts with oxygen in the presence of $Pd / Al_2O_3$?

An alkene $X$ with formula $C_4H_8$ does not exhibit geometrical isomerism. In the conversion of $X$ to $Y$,the correct sequence of reagents $A$ and $B$ used are ($Y$ gives iodoform test):
$X$ $\xrightarrow{A} \text{Intermediate}$ $\xrightarrow{B} Y$

The products $A$ and $B$ formed in the following set of reactions are:

What are $X$ and $Y$ in the following reaction?
Pent-$2$-ene $\xrightarrow[(ii) Zn / H_2O]{(i) O_3} X + Y$

Reaction of $tert.-$butyl alcohol with hot $Cu$ at $350 \, ^oC$ produces

Ozonolysis of an organic compound $A$ produces acetone and propionaldehyde in an equimolar mixture. Identify $A$ from the following compounds: