[求助]feifei 105

105.A survey of alumni of the class of 1960 at Aurora
                    University yielded puzzling results. When asked to indicate their academic rank, half of the respondents reported that they were in the top quarter of the graduating class in 1960.

Which one of the following most helps account for apparent contradiction above?

(A) A disproportionately large number of high ranking alumni responded to the survey.

(B) Few, if any, respondents were mistaken about their class rank.

(C) Not all the alumni who were actually in the top quarter responded to the survey.

(D) Almost all of the alumni who graduated in 1960 responded to the survey.

(E) Academic rank at Aurora
                    University was based on a number of considerations in addition to average grades.

答案是A，不明白这个题目啥意思，谁能分析一下各个选项吗？

拜托！

谢谢，明白了