Answer:
D
Step-by-step explanation:
The inner core (which is solid) is the hottest layer of the earth. It, therefore, contributes to heating up the outer core. The outer core is liquid and rotation of the earth (Coriolis effect) causes the molten rocks to swirl like a tornado. Because the outer core is mostly made of metals, that have lost electrons and hence charged (due to the enormous heat), the swilring effect causing an electric effect. This consequently causes the dynamo effect that creates a magnetic field. This magnetic field covers the earth and protects it from harmful radiation from the solar storms.