The correct answer is C: Earth's outer core contains liquids that conduct electricity.
According to the dynamo theory the outer core is said to be geodynamo. For any planet to be geodynamo, it should be rotating and contain a fluid medium in its interior, a supply of internal energy to drive the convection in the liquid. The Earth is “Goldilocks” geodynamo rotating steadily. The Coriolis force makes the convection current movement spiral. The liquid iron core is a very good electrical conductor which produces electric current which drives the magnetic field.
