Answer;
C. outer core.
Scientists think that the outer core, made of liquid iron and nickel, moves to produce Earth’s magnetic field
Step-by-step explanation;
-The earth's magnetic field is believed to be generated deep down in the Earth's core. The outer core, a 2,000 km thick layer of iron, nickel, and small quantities of other metals. It has lower pressure than the inner core which means the metal here is fluid.
-In the Earth, the liquid metal that makes up the outer core passes through a magnetic field, which causes an electric current to flow within the liquid metal. The electric current, in turn, creates its own magnetic field—one that is stronger than the field that created it in the first place.