Phosphorus Trichloride and Phosphorus Pentachloride Equilibrate in the Presence of Molecular

Phosphorus trichloride and phosphorus pentachloride equilibrate in the presence of molecular chlorine according to the following reaction: (g) + (g) → (g) An equilibrium mixture at 450 K contains = 0.124 bar, = 0.157 bar, and = 1.30 bar. What is the value of K_p at this temperature?

A) 66.8 bar^-1
B) 1.50 × 10^-2 bar^-1
C) 2.53 × 10^-2 bar^-1
D) 1.02 bar^-1
E) 4.63 bar^-1