The correct answer is the deployment of a Public cloud service model. The Public cloud is ideal for the company's needs because it allows multiple tenants to share the same infrastructure, which can lead to cost savings. This model also offers scalability to handle varying workloads and on-demand resource provisioning without the burden of managing the underlying infrastructure. The question seeks to identify understanding of cloud models, emphasizing the Public cloud's inherent characteristics of cost efficiency and scalability for deploying web applications.

Private cloud would not be the best fit because it is typically used by a single organization, not shared amongst multiple tenants, and often comes with higher costs and management overhead. Hybrid cloud involves a combination of public and private clouds but is not the most cost-effective solution for a company primarily interested in sharing resources and scalability. Community cloud, while shared among multiple organizations with common goals, may not offer the same degree of scalability and on-demand resource allocation as a public cloud.