请教LSAT 1-4-23

这个问题之前好像没人问过， 貌似就我一人搞不明白~~

High-technology medicine is driving up the nation's health care costs. Recent advances in cataract surgery illustrate why this is occurring. Cataracts are a major cause of blindness, especially in elderly people. Ten years ago, cataract surgery was painful and not always effective. Thanks to the new technology used in cataract surgery, the operation now restores vision dramatically and is less expensive. These two factors have caused the number of cataract operations performed to increase greatly, which has, in turn, drive up the total amount spent on cataract surgery.

7. Each of the following, if true, would support a challenge to the author's explanation of the increase in the number of cataract operations EXCEPT:

(A) The overall population of the nation has increased from what it was ten years ago

(B) Any one individual's chance of developing cataracts is greater than it was ten years ago.

(C) The number of older people has increased during the last ten years.

(D) Today, health insurance covers cataract surgery for more people than it did ten years ago.

(E) People who have had unsuccessful cataract surgery are left with more seriously impaired vision than they had before the surgery.

答案：E，我的问题是A为什么是削弱啊？总人口增加难道能推出动手术的人数增加么？我觉得两者之间没有必然联系啊，除非再添加一个假设，就是总人口增加，得病的人也增加

请各位帮我看看，我到底哪里像错了