What is the single most important value proposition for businesses to work in a Platform as a Service (PaaS) environment

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What is the single most important value proposition for businesses to work in a Platform as a Service (PaaS) environment?

A. As a cloud layer, developers are able to create and deploy their applications in a rapid release cycle, instead of needing to wait days or weeks to provision resources.
B. Developers have direct access to the underlying cloud infrastructure supporting their composable set of services and applications, allowing them to scale up as business grows.
C. Customers have a catalogue of composable, pre-tuned services from which to select and deploy onto the cloud platform. Developers no longer need to wait days or weeks to provision software instances.
D. Developers are able to rapidly deploy their applications in a rapid and iterative release cycle that is only possible using a cloud infrastructure. Customers can develop apps using their own proprietary programming and development tools.