The Presence of a Magnetic Field Is a Good Indication

Multiple Choice

The presence of a magnetic field is a good indication that:

A) the Earth's interior is similar to Mercury's, as both have fields.
B) a huge iron meteorite lies somewhere high up in the mantle, not in the core.
C) we have a liquid metal outer core, spinning rapidly as we rotate.
D) the Earth's interior must be completely molten to the center.
E) the Earth's interior has had time to solidify, with a rigid bar magnet created.