Chemical Equilibrium

\(\mathrm{A}_{(\mathrm{g})} \rightleftharpoons \mathrm{B}_{(\mathrm{g})}+\frac{\mathrm{C}}{2}(\mathrm{g})\) The correct relationship between \(\mathrm{K}_{\mathrm{P}}, \alpha\) and equilibrium pressure \(\mathrm{P}\) is