A publisher whose site contains a lot of user-generated content would like to ensure they don’t violate the AdSense content policies. Which of the following would NOT be an effective solution?

Disable ad serving until post is reviewed.
Enabling their users to report possible abuse by adding a “Report violations” link to every post.
Use Captcha verification to prevent automated posts.
Place the AdSense code only on content created by themselves, by their own staff or by users they can trust.
Develop a keyword filtering system to monitor the content.
Do nothing, as publishers are not responsible for monitoring the user-generated content on their site.