4.0 moles of argon and 5.0 moles of PCI5 are introduced into an evacuated flask of 100 liter capacity at 610 K. The system is allowed to equilibrate. At equilibrium, the total pressure of mixture was found to be 6.0 atm. The Kp for the reaction is
[Given : R = 0.082L atm K–1 mol–1]
(A) 2.25
(B) 6.24
(C) 12.13
(D) 15.24