Consider the Reaction Represented by the Equation: N₂(g)+ 3H₂(g)

Consider the reaction represented by the equation: N₂(g) + 3H₂(g) 2NH₃(g) .What happens to the equilibrium position when an inert gas is added to this system (as represented above) at equilibrium?

A) If the container is rigid,nothing happens to the equilibrium position.If the container is fitted with a moveable piston,the equilibrium position shifts.
B) If the container is rigid,the equilibrium position shifts.If the container is fitted with a moveable piston,nothing happens to the equilibrium position.
C) The equilibrium position shifts no matter what the container is like.
D) Nothing happens to the equilibrium position no matter what the container is like.
E) The value of the equilibrium constant must be known to answer this question.