D. Red dirt
The Outback is the enormous, remote center of Australia. "The Outback" is more obscure than those cities called "the bush" which is an area outside the central metropolitan areas. Unlike much of the Northerly Hemisphere, Australian dirt is very thick and millions of years old. The remnant of iron oxides has been able to acquire through millions of ages of weathering. Accidentally, although the red soil is rich, it is not of much utility because it is very poor in nutrients.
