Why do ionic compounds conduct electricity in molten state

Why do ionic compounds conduct electricity in the molten state?

A) Because ions are free to move in the molten state.
B) Because ions are fixed in the molten state.
C) Because molten state increases electrical resistance.
D) Because ionic compounds lose their charge in the molten state.

Correct Answer:

A) Because ions are free to move in the molten state.

Why do ionic compounds conduct electricity in molten state