The source of earth's magnetic field is solid magnetized iron in the core liquid magnetized iron in the core liquid iron in the core liquid metallic hydrogen in the core

The answer is liquid iron in the core. As the liquid iron churns, due to convection currents and Coriolis effect of the earth’s spin, in the inner core of the earth. The iron molecules/atoms, which are in charged particle form due to the high temperatures, move become akin to an electric current and produce magnetic fields. These magnetic fields cause increases electric currents in the core as a result of induction. This produces even more powerful  magnetic fields that span the outer space.