A reporting system delivers hundreds of .csv files to an Amazon S3 bucket each day. The company must convert these files to Apache Parquet and store the results in a transformed data bucket. Which solution will meet the requirement with the LEAST development effort?

AWS Glue is a fully managed ETL service that natively supports converting data formats like CSV to Parquet with minimal development effort. An AWS Glue crawler automatically discovers the schema of the CSV files, and an AWS Glue ETL job (often generated automatically or with minor modifications) can perform the conversion and write the output to the specified S3 bucket. Creating an Amazon EMR cluster with Apache Spark requires managing the cluster and writing a Spark application, which is more development effort. AWS Batch is suitable for general-purpose batch computing but requires writing and managing the transformation logic within a custom script, increasing development effort compared to Glue. An AWS Lambda function is suitable for smaller, event-driven transformations, but for hundreds of files daily, especially if they are large, managing the Lambda concurrency, memory, and execution time limits, and writing the entire transformation logic, would involve more development and operational overhead than Glue.