[单项选择]Students who entered lotteries and won spots in New York City charter schools performed better on state exams than students who entered the same lotteries but did not secure charter school seats, according to a study by a Stanford University economist being released recently.
Charter schools, which are privately run but publicly financed, have been faring well on standardized tests in recent years. But skeptics have discounted their success by accusing them of "creaming" the best students, saying that the most motivated students and engaged parents are the ones who apply for the spots.
The study’s methodology (研究方法) addresses that issue by comparing charter school students with students of traditional schools who applied for charter spots but did not get them. Most of the city’s 99 charter schools admit students by lottery.
The report is part of a multi-year study examining the performance of charter schools in New York City by Caroline M. Hoxby, a Stanford economist who
A. Students have to take state exams which are authoritative yardstick.
B. Students in charter schools know very well about how to win a lottery.
C. Students who perform worse on state exams have no access to charter schools.
D. Students in charter schools are superior to others in the aspect of state exams.