H₂ (G) + I₂ (G) → 2HI (G) Construct an Expression

H₂ (g) + I₂ (g) → 2HI (g) Construct an expression for the equilibrium constant K_p in terms of partial pressures of the reactant and product gases.

A)
$K_{\rho}=\frac{\rho_{H}^{2}}{\rho_{\mathrm{H}_{2}} \rho_{l2}}$
B)
$K_{\rho}=\frac{2 p_{\mathrm{Hl}}}{p_{\mathrm{H}_{2}} \rho_{l2}}$
C)
$K_{P}=\frac{\rho_{\mathrm{HI}}}{\rho_{\mathrm{H}_{2}}+\rho_{l2}}$
D)
$K_{\rho}=\frac{\rho_{H_{2}}\rho_{l2}}{\rho_{H 1}^{2}}$