What is the best way to revise sentence 4 to provide an appropriate thesis statement for the passage?
Answer choices for the above question

A. Using the moon as a fueling station could revolutionize space travel by making it more economical.

B. This would make it much easier—and more economical—for humans to venture further into space than previously thought possible.

C. Scientists want to establish a lunar colony and are working to solve the problems humans would face living on the moon.

D. Since this could revolutionize space travel by making it more economical, scientists are working to make a lunar fueling station a reality.