Option A is the correct approach as it leverages the Copy Data activity for data ingestion from various sources, the Data Flow activity for data cleansing and transformation, and Azure SQL Data Warehouse as the destination for loading the transformed data. This combination of features provides a comprehensive solution for the given scenario. Option B is not suitable as Azure Blob Storage is not a data warehouse, and Option C is not ideal for this use case as Azure Cosmos DB is a NoSQL database. Option D, while capable of handling IoT data, may not be the most efficient choice for general data ingestion and transformation tasks.