Which of the Following Conditions Would Force to Completion the Reaction

Which of the following conditions would force to completion the reaction?
2 N₂ (g) + 6 H₂O (g) + heat $\rightarrow$ 4 NH₃ (g) + 3 O₂ (g)

A) continual removal of N₂ gas
B) decrease the pressure on the reaction vessel
C) continual addition of NH₃ gas to the reaction mixture
D) increase reaction temperature