All the statements can be used to explain about Earth's magnetic field.
Earth's magnetic field is almost same to that of the bar magnet. The magnetic field of the earth occurs from its core. It has an inner core which is solid in nature. in the outer core, there is a motion of the liquid due to heat flow from the inner core to the core mantle boundary which proves that the outer core is liquid and moving. The Earth's core consists of iron and nickel as the Eddy currents in the iron and nickel liquid helps generating the Earth's magnetic field.
Hence, all the three statements are true and can be used to explain the Earth's magnetic field.
D. Electrons are shared between the bromine atoms and carbon atoms
Well, if a charger conductor is touched to another object or close enough to touching the object then the conductor can transfer its charge to that object. Conductors allow for electrons to be transported from particle to particle, so a charged object will always distribute its charge until the repulsive forces are minimized.