A Vessel Was Filled with NOCl Gas Until the Concentration

A vessel was filled with NOCl gas until the concentration was 0.398 mol L^?1. The temperature of the system was increased to 245 °C and the system was allowed to undergo the reaction, 2NOCl(g) 2NO(g) + Cl₂(g) , until equilibrium was attained. The physical chemistry students did a calculation and found that the [Cl₂] at that point was 0.0225 mol L^-1. Calculate the value of K_p at that temperature.

A) 1.22 × 10^-2
B) 1.55 × 10^-2
C) 1.45 × 10^-3
D) 4.46 × 10^-3
E) 6.61 × 10^-1