Which service model includes shared server resources for applications in the cloud?

The correct answer is C, multitenancy. In cloud computing, multitenancy is a core architectural principle where a single instance of a software application serves multiple customers, or tenants. In this model, the application can share its resources, such as data storage and processing power, among various users, while keeping their individual data segregated and secure. This allows for efficient resource utilization and cost savings, as the shared infrastructure can serve numerous clients without the need for separate resources for each.

Although the other service models are relevant in cloud computing, they represent different aspects. Infrastructure as a Service (IaaS) focuses on providing virtualized computing resources over the internet, where users can manage their own operating systems and applications. Software as a Service (SaaS) delivers software applications over the internet on a subscription basis, but it doesn't specifically highlight the shared nature of server resources. Platform as a Service (PaaS) offers a platform allowing customers to develop, run, and manage applications without dealing with the infrastructure, but it also does not emphasize the multitenant aspect as the primary feature. Therefore, multitenancy is the most accurate choice when considering the concept of shared server resources for applications in the cloud.