GWD-2的答案中是不是gmat和math&verbal弄反了？

我现在是这么看的，因为这样才可能和我的答案对得上大部分。

gmat中有个逻辑不明白，17Q

Q17:

The quality of unrefined olive oil is not actually defined in terms of acidity, yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality. The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity.

If the statements above are all true, which of the following conclusions is best supported by them?

When an olive oil is refined, the concentration of oleic acid in the oil is reduced. The quality of an unrefined olive oil can be determined only by accurately measuring its acidity. If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality. Free oleic acid is the only acid that unrefined olive oil contains. People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.

我选了D。因为我认为本文的结论是最后一句话，但是参考答案为C。

我认为C的意思，在文章的第二句中已经描述过，没有必要再重复。所以我觉得不对。

大家帮我看看？

文中第二句话正好能推出C,但是文中没有信息证明Free oleic acid is the only acid that unrefined olive oil contains.