Because the file arrives intermittently rather than on a predictable cadence, a File Drop Automation (C) is the correct trigger mechanism — it kicks off the automation the moment the file lands on the Enhanced SFTP location, satisfying the ' immediately imported ' requirement, in contrast to a Scheduled Automation (A), which only runs at fixed, predetermined intervals and would introduce unnecessary delay between file arrival and processing. Once imported, the requirement that contacts be ' segmented to enter a specific journey depending on the data inside the file ' describes routing different subsets of the imported data toward different journey entry sources, which is precisely what a SQL Query Activity (D) accomplishes: it evaluates the imported data ' s field values and writes matching subsets into the appropriate, journey-specific data extensions that then serve as entry sources for the correct journeys. Decision Split (B) is a Journey Builder activity that routes contacts already inside a single journey down different internal paths based on criteria — it does not determine which of several distinct journeys a contact should enter in the first place, which is the segmentation task described here; that pre-entry routing decision belongs to a Query Activity performed in Automation Studio before journey injection. Reference: File Drop Automations, Automation Studio Query Activity, Journey Entry Source Segmentation.