To meet the application development requirements for App1, which capability should you include in your recommendation?

Deployment slots allow you to deploy different versions of your application to separate environments (e.g., staging, production) within the same App Service plan. This enables testing new versions in a pre-production environment before swapping them into production, minimizing downtime and risk. Azure App Configuration is for centralizing application settings, not for managing deployments. An Azure Container Registry stores container images, which is relevant if App1 uses containers, but doesn't directly address the need for staged deployments. CI/CD sources refer to the repositories where your code lives and the pipelines that automate builds and deployments; while essential for modern development, they don't inherently provide the staged deployment capability that slots offer.