求教一道逻辑题

cptbtptp

The pharmaceutical industry argues that because new drugs will not be developed unless heavy development costs can be recouped in later sales, the current 20 years of protection provided by patents should be extended in the case of newly developed drugs. However, in other industries new-product development continues despite high development costs, a fact that indicates that the extension is unnecessary.

Which of the following, if true, most strongly supports the pharmaceutical industry's argument against the challenge made above?

(A) No industries other than the pharmaceutical industry have asked for an extension of the 20-year limit on patent protection.

(B) Clinical trials of new drugs, which occur after the patent is granted and before the new drug can be marketed, often now take as long as 10 years to complete.

(C) There are several industries in which the ratio of research and development costs to revenues is higher than it is in the pharmaceutical industry.

(D) An existing patent for a drug does not legally prevent pharmaceutical companies from bringing to market alternative drugs, provided they are sufficiently dissimilar to the patented drug.

(E) Much recent industrial innovation has occurred in products---for example, in the computer and electronics industries---for which patent protection is often very ineffective.

D选项到底是什么意思啊？看不懂，尤其provided they are sufficiently dissimilar to the patented drug. 是什么意思啊？

cptbtptp

thx!

zongtong

(D) An existing patent for a drug does not legally prevent pharmaceutical companies from bringing to market alternative drugs, provided they are sufficiently dissimilar to the patented drug.
一种药物的专利并不能从法律上禁止其他制药公司生产上市有类同效用的药物，如果这些药物和申请专利的药品显著不同的话。