The phrase the inventors claim

題目：

The phrase the inventors claim is used to a. cast doubt about how easy the GEN H-4 is to fly. b. prove that the flight speed and height are accurate. c. make it clear that a licence isn't needed to fly the GEN H-4 d. show that the inventors of the personal helicopter are clever
一道高二英語閱讀題，請教解題思路，謝謝！

解答：

解題思路： 請看第三段(GEN H-4)最後一句中的：the inventors claim it is as easy as riding a bicycle, 據此可知答案爲C. make it clear that a licence isn't needed to fly the GEN H-4
解題過程：
是這樣的
最終答案：見上文