The Standard Free Energy of Formation of Nitric Oxide, NO

The standard free energy of formation of nitric oxide, NO, at 1000. K (roughly the temperature in an automobile engine during ignition) is 78 kJ/mol. Calculate the equilibrium constant for the reaction
N₂(g) + O₂(g) 2NO(g)
At 1000. K.

A) 4.3 × 10^-10
B) 8.4 × 10^-5
C) 0.99
D) 1.8 × 10^-19
E) 7.1 × 10^-9