Which text about energy sources, such as solar, wind, and nuclear, most clearly uses a topical text structure?

(a) A pamphlet that explains where in the world different forms of energy are most used today.

(b) A website that describes energy sources according to when they were discovered.

(c) An Article that discusses the order of major developments related to energy usage.

(d) A book that describes each of the most popular energy sources available today.