开始集中训练逻辑了：）

有一题不明白：
Among the more effective kinds of publicity that publishers can get for a new book is to have excerpts of it published in a high-circulation magazine soon before the book is published. The benefits of such excerption include not only a sure increase in sales but also a fee paid by the magazine to the book's publisher.
Which of the following conclusions is best supported by the information above?
(A) The number of people for whom seeing an excerpt of a book in a magazine provides an adequate substitute for reading the whole book is smaller than the number for whom the excerpt stimulates a desire to read the book. (assumption?)
(D) The effectiveness of having excerpts of a book published in a magazine, measured in terms of increased sales of a book, is proportional to the circulation of the magazine in which the excerpts are published.
答案是A
这种类型的题目（Which of the following conclusions is best supported by the information above）应该怎么做阿？
我怎么觉得A选项是assumption，不是conclusion呢

哪位大侠指点一下，谢谢