The answer is D. A Supreme court Decision to move the Cherokee west of the Mississippi River. Here is text from Wikipedia,
"Indian removal was a genocide in the 19th century whereby Native Americans were forced by the United States government to leave their ancestral homelands in the eastern United States to lands west of the Mississippi River, specifically to a designated Indian Territory (roughly, modern Oklahoma)."
Apollo 11, in July 1969, climaxed the step-by-step procedure with a lunar landing; on July 20 astronaut Neil Armstrong and then Edwin (“Buzz”) Aldrin became the first humans to set foot on the Moon's surface.
