The correct answer is: B. PaaS
PaaS (Platform as a Service) is a cloud computing model that provides a platform for developing, testing, and deploying applications. The platform includes a set of tools and services that abstract away the underlying infrastructure, such as the operating system, hardware, and networking. This allows developers to focus on developing their applications without having to worry about the underlying infrastructure.
IaaS (Infrastructure as a Service) is a cloud computing model that provides access to computing resources, such as servers, storage, and networking. The resources are provided over the internet on a pay-as-you-go basis. This allows businesses to scale their computing resources up or down as needed without having to make a large upfront investment in hardware.
SaaS (Software as a Service) is a cloud computing model that provides access to software applications over the internet. The applications are hosted by the service provider and are accessed by users through a web browser. This allows businesses to use software applications without having to install and maintain them on their own infrastructure.
In the question, you add a software stack, such as an operating system and applications to the service. This means that you are providing a platform for developing, testing, and deploying applications. This is a PaaS model.