Three thermochemical equations are given below
i) ${\mathrm{C}}_{\left(\mathrm{graphite}\right)}+{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{CO}}_{2\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}=-\mathrm{x}\mathrm{kJ}{\mathrm{mol}}^{-1}$
ii) ${\mathrm{C}}_{\left(\mathrm{graphite}\right)}+\frac{1}{2}{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{CO}}_{\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}=-\mathrm{y}\mathrm{kJ}{\mathrm{mol}}^{-1}$
iii) ${\mathrm{CO}}_{\left(\mathrm{g}\right)}+\frac{1}{2}{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{CO}}_{2\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}=-\mathrm{z}\mathrm{kJ}{\mathrm{mol}}^{-1}$
Based on the above equations, find out which of the relationship given below is correct