Question

英语阅读理解一道题，求大神解答。

Dr. Krugman believes that when we stop noticing advertisements, we lower our defenses, allowing the messages of the advertisements to be taken in and stored, ready to be triggered into action at the right moment. He says that the effects of advertising on the individual are small, but over a period of time they have a powerful effect on the masses.
When asked about the power of advertising in research surveys, most people agree that it works, but not on them. Almost everyone believes that they have complete control over how thousands of ads they see every day affect them.

问:When asked about the power of ads, most people agree that ads are ineffective on （）.
A．individuals
B．masses
C．others
D．them

答案是d 可我怎么看都觉得c对啊 不是说“but not on them”吗？

Answer 1

When asked about the power of advertising in research surveys, most people agree that it works, but not on them.
当被问起宣传在研究调查中的作用时，大多数人会说宣传确实有用，但不是对他们。
也就是说宣传对他们没有用，也就是 ads are ineffective on them
题里面问的是ineffective，原文里面是 effective/work, but not
你得把句子看全了再选