Born in Italy in 1853, Maria Spelterini emigrated to the United States as a young woman and quickly became known for her breathtaking stunts. In 1876, the 23-year-old Spelterini became the only woman ever to cross the Niagara Gorge over a period of 18 days on a tightrope.
A) No change
B) on a tightrope, accomplishing that feat over a period of 18 days.
C) over a period of 18 days, she did this on a tightrope.
D) over a period of 18 days and, furthermore, doing this on a tightrope.
I had thought it would be A), but the answer is B). I think both works, but why would A) be wrong?