Answer: Ad Words policies can help ensure ads are useful, varied, relevant, and safe for web users
Explanation: Google Ads do have a policy for the ad display which requires that the ads should be secured, relevant and safe for the users on the web. Google Ads positively review every Ads that is created or has been changed in some terms as their policy. It maintains the standard and relevancy on the web and no objectionable content gets posted .
This might be the reason that the client's ads are disapproved because he/she is not aware of the Google's ads policies.