If you’re getting website traffic from numerous sources and want to find out where your website users are coming from, such as “organic search” or “referral,” which dimension will show you that information?

The "Session primary channel group (Default Channel Group)" dimension in Google Analytics categorizes traffic sources into high-level groupings like "Organic Search," "Direct," "Referral," "Paid Search," and "Social." This provides a quick overview of where users are coming from. While "Session source / medium" offers more granular detail (e.g., "google / organic" or "facebook.com / referral"), the question specifically asks for broad categories like "organic search" or "referral," which aligns perfectly with the Default Channel Group. "Google Ads campaign" is too specific, only showing traffic from Google Ads. "Page title and screen class" describes content viewed, not the traffic source.