What causes the Earth's magnetic field?

A. circulation of Van Allen belts around the planet

B. presence of charged particles in the inner core

C. charged particles from solar wind hitting the magnetosphere

D. movement of charged particles in the outer core

Our planet's magnetic field is believed to be generated deep down in the Earth's core ... The Coriolis force, resulting from the Earth's spin, also causes swirling whirlpools. This flow of liquid iron generates electric currents, which in turn produce magnetic fields.