Which of the following is not correct?

The bleaching action of $SO_2$ is due to its:

Upon heating $KClO_3$ in the presence of a catalytic amount of $MnO_2$,a gas $W$ is formed. Excess amount of $W$ reacts with white phosphorus to give $X$. The reaction of $X$ with $HNO_3$ gives $Y$ and $Z$.
$(1)$ $W$ and $X$ are,respectively:
$[A]$ $O_3$ and $P_4O_6$
$[B]$ $O_2$ and $P_4O_6$
$[C]$ $O_2$ and $P_4O_{10}$
$[D]$ $O_3$ and $P_4O_{10}$
$(2)$ $Y$ and $Z$ are,respectively:
$[A]$ $N_2O_3$ and $H_3PO_4$
$[B]$ $N_2O_5$ and $HPO_3$
$[C]$ $N_2O_4$ and $HPO_3$
$[D]$ $N_2O_4$ and $H_3PO_3$
Give the answer of question $(1)$ and $(2)$.

What is the product formed when $SO_2$ reacts with an aqueous solution of sodium hydroxide?

Which of the following statements is correct for oleum?

Which of the following is the most basic oxide?