Zinc oxide is reduced at a constant temperature in a closed reactor using ZnO$(s)$ and $C(s)$ as the only starting materials. The following reactions are assumed to be at thermodynamic equilibrium:

ZnO$(s)+C(s)=Zn(g)+CO(g)$

$2CO(g)=C{O}_2(g)+C(s)$

Assume ideal gas $2$Behavior. Based on mole balance, the relationship applicable to the system at equilibrium is

$($A$)p_{Zn}=p_{CO}+2p_{CO2}$

$($B$)p_{Zn}=2p_{CO}+p_{CO2}$

$($C$)p_{Zn}=p_{CO}+p_{CO2}$

$($D$)p_{Zn}=0\mathrm{.}5p_{CO}+2p_{CO2}$