At room temperature, lithium reacts with nitrogen to produce solid $\text{Li}_3\text{N}$. As shown, three vessels of equal volume are linked by taps A and B. Initially, A and B are closed; the left-hand vessel is evacuated, the middle vessel contains the reaction shown at equilibrium, and the right-hand vessel holds lithium only. Which action would result in the equilibrium mixture containing the greatest amount of ammonia?
- AKeep both A and B closed.
- BOpen both A and B.
- COpen A only.
- DOpen B only.