A data engineer must create a Lambda function that converts uploaded .csv files in S3 to Parquet and must trigger only when a user uploads a .csv file. Which solution provides this behavior with the least operational overhead?

The correct solution directly triggers the Lambda function from an S3 event notification for object creation, specifically filtering for .csv suffixes. This minimizes operational overhead by avoiding intermediate services. The incorrect option using s3:ObjectTagging: is wrong because the trigger needs to occur on object creation, not tagging. Tagging would require an additional step after upload. The option using s3: as the event type is too broad and would trigger for all S3 events, leading to unnecessary invocations and potentially higher costs, even with a filter rule. The s3:ObjectCreated: event type is more specific and efficient. The option involving an Amazon SNS topic adds an unnecessary layer of complexity and operational overhead. While it would work, directly invoking the Lambda function from S3 is simpler and more efficient for this use case.