题目：

The phrase the inventors claim is used to a. cast doubt aut 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
一道高二英语阅读题，请教解题思路，谢谢！

答案参考：

解题思路： 请看第三段(GEN H-4)最后一句中的：the inventors claim it is as easy as riding a bicycle, 据此可知答案为C、 make it clear that a licence isn't needed to fly the GEN H-4
解题过程：
是这样的
最终答案：见上文