Which service model allows the organization to customize development while a third-party vendor provides infrastructure?

The service model that allows an organization to customize development while a third-party vendor provides the underlying infrastructure is Platform as a Service (PaaS). PaaS provides a platform that includes both hardware and software tools available over the internet, enabling developers to build applications without having to manage the underlying infrastructure. This allows for customization and development flexibility, as developers can focus on creating applications while benefiting from the utility of scalable resources.

In contrast, Software as a Service (SaaS) offers fully developed applications that users access over the internet, meaning customization is limited since the application is already built and hosted. Infrastructure as a Service (IaaS) provides raw infrastructure resources like virtual machines and storage, allowing for significant customization but placing the onus of development squarely on the organization. Lastly, a Community Cloud is a collaborative model where infrastructure is shared among specific communities with shared concerns, but it does not inherently offer the same level of customization for applications as PaaS. Hence, PaaS stands out for its tailored development capabilities facilitated by the vendor-managed infrastructure.