Which service is primarily used for data cleansing and transformation in AWS?

AWS Glue is primarily designed for data cleansing and transformation within the AWS ecosystem. It is a fully managed extract, transform, load (ETL) service that enables users to prepare and load data for analytics. With AWS Glue, users can discover, catalog, and transform data, making it easier to clean and suit the data for analysis or machine learning models.

It offers a range of features, such as data cataloging, which serves as a central repository to store metadata, and the ability to write ETL jobs using either Python or Scala. AWS Glue's serverless architecture eliminates the need to manage infrastructure, allowing users to focus on their data processing tasks. This is particularly valuable in situations where large volumes of data from various sources need to be cleaned or transformed before analysis.

The other options serve different purposes: AWS Snowball is typically utilized for data transfer at scale, AWS Batch is focused on running batch computing jobs, and AWS QuickSight is a business intelligence service primarily used for visualizing data rather than for cleansing or transformation.