What happens to the following equilibrium when neon (Ne) is added to double the total pressure at constant volume?

N₂(g)+3H₂(g)⇌2NH₃(g)

a. The equilibrium shifts to the right to produce more NH₃(g).
b. The equilibrium shifts to the left to produce more NH₃(g).
c. The concentration of NH₃(g) remains the same.
d. The concentration of N₂(g) remains the same.