逻辑的一个题目不是很明白，帮我看看哪里错了

小皮球PAL

31. Cheever College offers several online courses via
remote computer connection, in addition to traditional
classroom-based courses. A study of student
performance at Cheever found that, overall, the
average student grade for online courses matched
that for classroom-based courses. In this calculation
of the average grade, course withdrawals were
weighted as equivalent to a course failure, and the
rate of withdrawal was much lower for students
enrolled in classroom-based courses than for students
enrolled in online courses.
If the statements above are true, which of the
following must also be true of Cheever College?
(A) Among students who did not withdraw, students
enrolled in online courses got higher grades, on
average, than students enrolled in classroombased
courses.
(B) The number of students enrolled per course at
the start of the school term is much higher, on
average, for the online courses than for the
classroom-based courses.
(C) There are no students who take both an online
and a classroom-based course in the same
school term.
(D) Among Cheever College students with the best
grades, a significant majority take online, rather
than classroom-based, courses.
(E) Courses offered online tend to deal with subject
matter that is less challenging than that of
classroom-based courses.
正选 A
我的理解 ONLINE COURSE 退出的人多，但是2者平均分确实一样的，所以ONLINE的高分多。这是题意
不知道如何成立？比如现实COURSE的高分很多，低分也很多，2者一平均从而使平均分到C
ONLING上面人的分数浮动没有那么多，都是C。
按照我的理解题目也成立，是不是我看错了。或者是course WITHDRAWLS在这里是不及格的意思?
请教了

piaopiao633

我觉得是不是这句话：In this calculation of the average grade, course withdrawals were weighted as equivalent to a course failure
online course退出的人少，说明course failure的人也少--->平均分比classroom based courses的人高

open to discuss

小皮球PAL

我重新看了一遍，应该是我把course failure理解错了，这里应该理解为不及格的意思吧，谢谢了