In the following sequence of reactions $\mathrm{X}, \mathrm{Y}$ and $\angle$ are, respectively
(a) $\mathrm{KClO}_{3}, \mathrm{HPO}_{3}$ and $\mathrm{C} \mathrm{I}_{2} \mathrm{O}_{i}$
(b) $\mathrm{KClO}_{4}, \mathrm{I} \mathrm{IPO}_{3}$ and $\mathrm{Cl}_{2} \mathrm{O}_{\mathrm{r}}$
(c) $\mathrm{Cl}_{2} \mathrm{O}_{2}, \mathrm{I} \mathrm{IPO}_{3}$ and $\mathrm{KClO}_{4}$
(d) $\mathrm{KClO}_{3}, \mathrm{H}_{3} \mathrm{PO}_{4}$ and $\mathrm{Cl}_{2} \mathrm{O}_{2}$