阅读求助：naive=credulity？

谦虚的小公鸡UID: 2961678

1992年4月section 4 长  L43~46

But those who reject the idea of rhetoric because they believe it deals in lies and who at the same time hope to move people to action, must either be liars themselves or be very naive.


21.  According to the passage, to reject rhetoric and still hope to persuade people is
B) an indication either of dishonesty or of credulity. (标准答案 ）


我知道naive有credulity的意思，但你怎么确定这里作者指的是credulity的意思而不是innocent的意思？