This scenario cleanly separates two distinct kinds of work, and the correct architecture assigns each to the tool best suited for it. Automation Studio is the right place to process and segment the hourly batch file drop — importing the file, validating/cleaning the data, and preparing it into a properly structured data extension — because batch file ingestion and bulk data preparation are exactly what Automation Studio ' s Import, Query, and Verification activities are optimized for. Once prepared, Journey Builder is the correct tool for the actual welcome series itself, since it natively supports multi-step message sequencing, wait periods between messages, and — critically — Send Time Optimization, a feature available specifically within Journey Builder ' s message activities to automatically time each individual send for optimal engagement per recipient, which the scenario explicitly requires. Option A skips the batch-processing strength of Automation Studio and asks Journey Builder to also handle raw file segmentation, which is not its designed purpose. Option C omits Journey Builder ' s send-time optimization capability entirely, which Automation Studio ' s Send Activity does not natively provide. Option D substitutes Email Studio, which lacks journey-based sequencing and optimized send-time logic altogether. Reference: Journey Builder Send Time Optimization, Automation Studio Batch Processing.