Select the incorrect statement below about the Earth's magnetic field. a. The declination of the Earth's magnetic field changes on decadal timescales, but on average the Earth's magnetic pole aligns with the axis of rotation. b. The inclination of the magnetic field varies from being horizontal near the equator to very steep at the poles. c. The magnetic field forms as a result of convection of liquid iron in the Earth's liquid inner core. d. The polarity of the Earth's magnetic field switches directions on timescales of hundreds of thousands to millions of years. e. Study of the magnetic properties of rocks played an important part in the development of the plate tectonic theory.