From June through August 1987, Premiere Airlines had the best on-time service of 10 United States airlines. From January through March 1988, Premiere Airlines had the worst on-time service of the 10 airlines. The on-time performance ranking of the other nine airlines relative to each other remained unchanged.
Which of the following, if true, would most contribute to an explanation of the facts above?
(A) Although Premiere Airlines only revoked its policy of routinely holding flights for late passengers in the fall of 1987, the other nine airlines never had that policy.
(B) remiere Airlines reduced its business by 10 percent when it raised its rates in the fall of 1987 to compensate for rising gasoline costs.
(C) remiere Airlines bought five new planes in the fall of 1987 that proved to have fewer mechanical problems than the ones they replaced.
(D) remiere Airlines serves New England, which has heavy winter snowfalls, whereas the other airlines do .;} most of their business in warmer regions of the country.
(E) Although all 10 airlines strive to keep their flights on schedule, overcrowded airports increased flight delays for all 10 airlines in January 1988 as compared with June 1987.

答案D只说明了为什么在冬季成绩差的原因，没有说明夏季为什么best，难道解释题是不充分的解释？还是排版的时候弄掉了？

The argument doesn't care why 冬季成绩差 and 夏季为什么best, all it wants is the reason why there is such a big discrepancy between the two. If in summer it is the best, then in winter it should be the best too.  D says exactly the reason why the perfomance in the two seasons are so different.

the requirements of the question is to give a good explaination for the fact that the great difference in on-time issue in the same company in different seasons.

we should explain that difference occured.We make a link between the season and discrpency servece in on-time issue.We know because of the bad weather ,the on-time issue badly performed in winter is not beacuse of the bad servece which never happened in summer.So ,if the weather factor is removed ,the quality servece will be the same .

红字部分不赞成。知道了the worst on-time service是由于天气造成，但是不知道the best on-time service是否会和其它的月份一样。

D只说明了冬季worst，没有说明为什么夏季best。如果不考虑天气因素，仍然存在夏季和平时的差别。

you thought too much about this issue ,my inferration is no the key to theis question.What we should do is to explain why such the difference in server occured,not what will happen if the season is not the fact.

We find out that weather changing in winter is understandable explaination for this question.Tha's all ,WE FINISH THE MISSSION.

What will happen if we remove such weather factors,positive or nagetiative,we don't know.But one thing is for sure ,if the weather factor put into effect ,such argument wil be understandable.

Which of the following, if true, would most contribute to an explanation of the facts above?

the argument will be better served when we can expalin either why the company did better in summer or why they did worse in winter.If either of them is well explained ,the question will be answered.Becase such explaination will draw the difference more closer than ever.

Since ther is no choice saying why better in summer,let's thought about the adverse factor.