Rosa's work finding the median of a set of test scores is shown below. Left-brace 80, 70, 90, 80, 90, 65, 100, 100, 90 right-brace Which statement best describes Rosa's first error? a She should have reordered the elements from least to greatest. b She should have added the elements and divided by 9. c She should have found the difference between the first and last elements. d She should have counted repeated elements only once.