With the exception of the last sentence, all sentences are fluidly written and clearly connected between each other. In the case of the last example, the lack of transitional phrases between the two sentences creates a disconnection between the concepts expressed. While we might still be able to understand these sentences, we need to make the transition happen for ourselves as it was not included in the example.
Therefore, your best answer is option D.
Physical geography: Grassy hills / Dirt
Agriculture : Cash crops like cotton
Industry : Growing crops on farm land
Anthropology is the study of culture
Witnesses?
Your question doesn't really have all the information necessary to have an accurate answer.
