Step 1: Concept
Electrical conductivity in the fused (molten) state requires the presence of free ions.
Step 2: Meaning
Ionic compounds dissociate into ions when melted, so they conduct electricity.
Step 3: Analysis
Covalent compounds consist of neutral molecules and do not possess free ions or electrons to carry charge in the fused state (unless they react with water to ionize).
Step 4: Conclusion
Statement (C) is incorrect because covalent compounds are generally non-conductors in the fused state.
Final Answer: (C)