For the described requirements, Cloud Foundry runtime and Kyma runtime are the most suitable for building the front-end app. * SAP BTP, Cloud Foundry Runtime: * Device Compatibility: Supports creating mobile-optimized front-end apps. * Scalability: Provides auto-scaling capabilities based on administrator-defined parameters. * SAP BTP, Kyma Runtime: * A Kubernetes-based runtime that supports microservices architecture, ideal for lightweight and scalable apps. * Offers native auto-scaling features, meeting the scalability requirements for the app. * Why Not Other Options? * C (Neo Environment): Outdated and does not offer modern scalability or compatibility for mobile apps. * D (ABAP Environment): Suitable for extending backend logic but not optimal for building scalable front-end applications. References: * SAP Cloud Foundry Runtime Overview * SAP Kyma Runtime Documentation