Journey Builder ' s Salesforce Campaign Member entry source is the native, event-driven mechanism specifically designed to inject a contact into a journey the moment they are added as a Campaign Member to a designated Salesforce Campaign — precisely matching the trigger condition described (Contact added as a Campaign Member to the Loyalty Members ' Campaign) — and the journey ' s Email Activity then sends the welcome message promptly upon that entry event, all natively within the existing Marketing Cloud Connect integration. This is the correct, purpose-built, real-time-triggered pattern for Campaign-Member-driven welcome emails. Option A ' s Content Builder Send Flow is designed for one-time, ad hoc sends directly to a Salesforce Report or Campaign audience as a snapshot at the moment of sending — it is not an ongoing, event-driven trigger that automatically fires a welcome email each time a new member is added over time. Option B ' s scheduled Automation with a Query Activity introduces batch-processing delay and requires manually re-querying for new Campaign Members on each run, lacking the immediate, native entry-event triggering that Journey Builder ' s Campaign entry source provides. Option D, creating an import definition, is unrelated to triggering an outbound email based on Campaign membership changes. Reference: Journey Builder Salesforce Campaign Entry Source.