- AdWords campaigns
- Email campaigns
- AdWords and email campaigns
- None of the above
By adding campaign parameters to your URLs, you can identify the campaigns that send traffic to your site. When a user clicks a referral link, these parameters are sent to Analytics, so you can see the effectiveness of each campaign in your reports. Google Adwords gives you an option to track campaign using auto-tagging.
Learn more here: https://support.google.com/analytics/answer/1033863