Identify the true statement. Choose one:

A. The outer core conducts because of thermal convection.

B. The base of the outer core is always denser than the upper part of that layer.

C. The Earth's magnetic field is generated in the liquid outer core.

D. The inner core is getting smaller.

Option (C)

Explanation:

The outer core of the earth is liquid in nature, where they are comprised of dense molten rocks, which flows continuously due to the heat energy radiated from the extreme core of the earth, having a very high temperature. This flow of liquid rocks across the present magnetic field lines of force generates an electric current which subsequently produces the magnetic field. This process of producing magnetic fields is commonly termed as advection.

Thus, the correct answer is option (C).