Scenario: An e-commerce platform is undergoing Use Case Testing. A use case involves the process of adding items to the shopping cart and proceeding to checkout. Which type of testing would be most appropriate to ensure that this use case functions correctly?

System Testing is most appropriate for ensuring that the entire process of adding items to the shopping cart and proceeding to checkout works correctly. It involves testing the system as a whole to validate that all components work together seamlessly. User Acceptance Testing (UAT) is typically done by end-users to ensure the system meets their requirements, but it might not cover the entire process as comprehensively as System Testing. Integration Testing and End-to-End Testing may not specifically focus on the described use case.