Which of the following would it be most useful to establish in evaluating the argument?
A. When, if ever, will production of oil in Malvernia outstrip production of natural gas?
B. Is Malvernia among the countries that rely most on imported oil?
C. What proportion of Malvernia's total energy needs is met by hydroelectric, solar, and nuclear power?
D. Is the amount of oil used each year in Malvernia for generating electricity and fuel for transportation increasing?
E. Have any existing oil^burning heating systems in Malvernia already been converted to natural gas- burning heating syste
Premise: convert heating system from oil to gas; produces more gas than it uses; oil production is increasing
Conclusion: If these trends in fuel production and usage continue, Malvernian reliance on foreign sources for fuel is likely to decline soon.
OA: D
我不理解的是，原文的结论里作者已经明确了，他所说的燃料生产和使用保持趋势是他的假设。作者并没有肯定地说这些趋势一定会保持。
而正确答案评估的是事实上该趋势能不能保持。
这样的评估对作者的推理也有削弱作用吗？
以及，该假设是出现在结论中的。如果正确答案对该假设有削弱作用，herl逻辑中说的直接削弱结论不是不能反驳推理吗？还是说我的前提和结论就找错了……
想了很久都想不懂，求大神解答
