SAT English Practice Question

The author of a recent book on the history of the American West wrote the following sentence: "As a result of the vast distances and difficult terrain, the development of the West was a long and arduous process, and it took centuries." Which choice provides the most effective and concise revision of this sentence?

1. A.The development of the West was a long and arduous process due to the vast distances and difficult terrain. It took centuries.
2. B.The development of the West was a long and arduous process, taking centuries, as a result of the vast distances and difficult terrain.
3. C.The development of the West, as a result of the vast distances and difficult terrain, was a long and arduous process that took centuries.
4. D.Due to the vast distances and difficult terrain, the development of the West was a long and arduous process, taking centuries.