When setting up Floodlight activities for a call-tracking service, what should the primary source of conversions be?

When integrating a call-tracking service with Floodlight, the primary source of conversions should be "Offline activity." This is because calls originating from ads are typically tracked by the call-tracking service and then imported into DoubleClick Search (now Search Ads 360) as offline conversions. This ensures that the call data, which happens outside the immediate online user journey, is correctly attributed. "All transactions" and "All actions" are too broad and would include online conversions that are not relevant to call tracking. "Selected conversions" is also too general and doesn't specifically address the unique nature of call-tracking data.