Final answer:
The correct statement regarding covalent electrolytes is that they must yield ions in water.
Step-by-step explanation:
Covalent electrolytes are covalent compounds that chemically react with water to produce ions. Therefore, the correct statement regarding covalent electrolytes is that they must yield ions in water (option c).
Unlike ionic compounds, which dissociate into ions when dissolved in water, covalent electrolytes undergo chemical reactions with water to form ions. For example, acids and bases, which are covalent electrolytes, ionize in water to yield H+ and OH- ions respectively.