A rock sample has a mass of $2.00\,\text{g}$. It includes calcium carbonate, with no other basic substances present. It exactly neutralises $36.0\,\text{cm}^3$ of $0.500\,\text{mol dm}^{-3}$ hydrochloric acid. What percentage of the $2.00\,\text{g}$ rock sample is calcium carbonate?
- A22.5%
- B45.0%
- C72.0%
- D90.1%