A manufacturing plant produces a single daily log file at 02:00. You have a Cloud Dataflow job to process it once per day as cheaply as possible. What should you do?

An App Engine Cron job is the most appropriate solution because it allows for scheduled execution of tasks, aligning with the requirement to process the log file once per day. This method is cost-effective as it only runs the Dataflow job when needed. Manually starting the job is inefficient and prone to human error. Converting to streaming is unnecessary and more expensive, as the log file is generated only once daily, making real-time processing overkill. Switching to Cloud Dataproc is an alternative processing engine, but doesn't address the scheduling requirement directly, and Dataflow is already specified as the processing tool.