Final answer:
Terra Rossa is the soil type found in the eastern US that is rich in iron, known for its red color, which is a result of its iron content. Option D is correct.
Step-by-step explanation:
The type of soil found in the eastern US that is rich in iron is Terra Rossa. The presence of iron gives Terra Rossa its characteristic red color, indicating that the soil is iron-rich. This type of soil is commonly associated with regions that experience a Mediterranean climate, but variations can be found in the southeastern United States.
In relation to the southeastern US, it is important to mention the famous "red dirt" of Georgia and Alabama; however, unlike Terra Rossa, which is generally fertile due to its high iron content, the red dirt found in Georgia and Alabama is not ideal for many crops due to issues such as nutrient leaching caused by over-abundant rainfall.
Therefore, the answer is D) Terra Rossa.