If acid is added to salt X, a gas is given off that makes limewater turn milky. If sodium hydroxide is added to salt X, a gas is given off that turns litmus paper blue. What is X?
- A$\text{CaCO}_3$
- B$(\text{NH}_4)_2\text{CO}_3$
- C$\text{NH}_4\text{NO}_3$
- D$\text{ZnCO}_3$