It can be inferred from the passage that ______.
A．there were altogether only two schools--the high school and the middle school in the small town where this story took place
B．polystyrene is the major factor that has done harm to the protective ozone layer of the atmosphere around the earth
C．the Board of Education actually had known the harmful effects of polystyrene on the environment before making the decision
D．Vogt and her classmates at last managed to persuade the Board of Education into changing their decision wish their academic knowledge