Three thermochemical equations are given below

$\left(\mathrm{i}\right) {\mathrm{C}}_{(\mathrm{graphite})}+{\mathrm{O}}_{2( \mathrm{g})}\to {\mathrm{CO}}_{2\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}°=\mathrm{x} \mathrm{kJ}{ \mathrm{mol}}^{-1}$

$\left(\mathrm{ii}\right) {\mathrm{C}}_{(\text{graphite) }}+1/2{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{CO}}_{\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}°=\mathrm{y} \mathrm{kJ}{ \mathrm{mol}}^{-1}$

$\left(\mathrm{iii}\right) {\mathrm{CO}}_{\left(\mathrm{g}\right)}+1/2{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{CO}}_{2\left(\mathrm{g}\right)};{\mathrm{\Delta }}_{\mathrm{r}}\mathrm{H}°=\mathrm{z} \mathrm{kJ}{ \mathrm{mol}}^{-1}$ Based on the above equations, find out which of the relationship given below is correct.