In which state does the ionic compounds conducts electricity? 

Molten

The correct answer is option 3. Molten.

Ionic compounds conduct electricity in the molten state and in aqueous (dissolved in water) solutions.

In the solid state, ionic compounds typically do not conduct electricity because the ions are held in fixed positions within the crystal lattice and cannot move freely to carry electrical charge. However, when ionic compounds are melted (in the molten state) or dissolved in water, the bonds between the ions are broken, and the ions are free to move. This mobility of ions allows the compound to conduct electricity. So, the correct answer is Molten.