第二遍看OG，但对这个195还是有些小问题，盼NN指教。

195. A proposed change to federal income tax laws would eliminate deductions from taxable income for donations a taxpayer has made to charitable and educational institutions. If this change were adopted, wealthy individuals would no longer be permitted such deductions. Therefore, many charitable and educational institutions would have to reduce services, and some would have to close their doors. The argument above assumes which of the following? (A) Without the incentives offered by federal income tax laws, at least some wealthy individuals would not donate as much money to charitable and educational institutions as they otherwise would have. (B) Money contributed by individuals who make their donations because of provisions in the federal tax laws provides the only source of funding for many charitable and educational institutions. (C) The primary reason for not adopting the proposed change in the federal income tax laws cited above is to protect wealthy individuals from having to pay higher taxes. (D) Wealthy individuals who donate money to charitable and educational institutions are the only individuals who donate money to such institutions. (E) Income tax laws should be changed to make donations to charitable and educational institutions the only permissible deductions from taxable income.

A，B，E如果取非都能对结论起到否定的作用。为什么单单选择了A？是因为B和E中的only太过绝对？

谢谢。

 but D also filled the gap between "wealthy individuals" and "who donate

money to such institutions".

and if it negnative, the conclusion cannot hold.

so , why? thanks very much.

yeah, i got it now.

thanks very much .

有道理啊。真乃niuniu也。

原文是，如果法案实施，富人捐助者将不能享受减税优惠。因此...

BD成立，不能必然得出结果。因为如果富人不顾减税优惠政策的取消，依旧捐款的话，原文结轮就不会成立