You need a GUI-based object sink into Cloud Storage that supports customer-managed encryption keys (CMEK) and accepts various file formats (Parquet, CSV). Which tool should you use?

Cloud Data Fusion is the correct choice because it is a fully managed, GUI-based data integration service that supports a wide range of data sources and sinks, including Cloud Storage. It inherently supports CMEK for data at rest in Cloud Storage and can handle various file formats like Parquet and CSV through its extensive plugin ecosystem. Storage Transfer Service is primarily for large-scale data transfers between storage systems, not a general-purpose GUI-based ETL tool for continuous ingestion. Dataflow is a powerful serverless data processing service, but it's code-centric (Java, Python, SQL) rather than GUI-based for defining data pipelines. BigQuery Data Transfer Service is designed specifically for transferring data into BigQuery, not Cloud Storage.