Final answer:
Calcium carbonate (Option D) is the compound that is insoluble in water due to the strong ionic attractions within its crystal structure that do not allow it to readily dissolve.
Step-by-step explanation:
The compound that is insoluble in water among the choices given is calcium carbonate (Option D). While many inorganic compounds are soluble in water, such as sodium chloride and ammonium nitrate, there are exceptions based on the solubility rules. Compounds containing the carbonate ion (CO32-) tend to be insoluble, with some exceptions such as those involving alkali metal cations. Calcium carbonate is a classic example of a compound where the ionic attraction within the crystal lattice is strong enough that it does not readily dissolve in water, unlike soluble compounds like sodium carbonate (Option A), potassium nitrate (Option B), or ammonium chloride (Option C). Therefore, calcium carbonate remains as a solid precipitate when mixed in water.