The Requirement(s) for the Generation of a Powerful Magnetic Field

Multiple Choice

The requirement(s) for the generation of a powerful magnetic field in a Jovian planet (e.g., Jupiter, Saturn) appear(s) to be a

A) liquid "metal" core and interior, and very slow rotation.
B) solid iron core forming a permanent magnet.
C) liquid "metal" interior and relatively rapid rotation.
D) solid interior throughout the planet and slow rotation.