The correct answer is A (App Engine). App Engine is a fully managed platform-as-a-service (PaaS) that automatically handles infrastructure concerns like scaling, patching, and monitoring, thus significantly reducing operational overhead. It allows developers to easily stage new versions of applications in the production environment and allows for seamless promotion of these versions to production by the operations team. This minimizes the need for manual configuration and management, making it an optimal choice for companies looking to streamline operations and manage applications with reduced operational complexity.