Which of the following statements best summarizes the main point of the passage? A. Charter schools, despite their merits, fail to overcome the long-standing problems in public education. B. Recent studies have shown that charter schools have had a revolutionary effect on student achievement. C. Freeing schools from some of the restrictions that govern them has caused a change in education since 1991. D. Charter schools have created a whole new way of educating children that did not previously exist. E. Assessments of charter schools' performance have reinforced the position that rigid rules and regulations are stifling academic achievement.