Nitrogen Trifluoride Decomposes at to Form Nitrogen and Fluorine Gases $\rightleftharpoons$

Nitrogen trifluoride decomposes at to form nitrogen and fluorine gases according to the following equation: 2NF₃(g) $\rightleftharpoons$ N₂(g) + 3F₂(g)
2) 50-L reaction vessel is initially charged with 1.22 mol of NF₃ and allowed to come to equilibrium at 800 K. Once equilibrium is established, the reaction vessel is found to contain 0.0194 mol of N₂. What is the value of K_p at this temperature? (R = 0.0821 L?atm/mol?K)

A) 2.68 × 10^-6
B) 1.91 × 10^-3
C) 1.79 × 10^-3
D) 2.77 × 10^-6
E) 4.43 × 10^-7