A software company needs a cloud-based environment that allows developers to write, test, and deploy applications without managing the underlying infrastructure. Which cloud service model is being used?

SaaS delivers software applications over the internet, allowing users to access software without needing to install or manage it on their local devices. While SaaS provides end-user applications, it does not offer the development environment or tools needed for developers to build and deploy applications, making it unsuitable for the company's needs.

Public cloud refers to cloud services offered over the internet by third-party providers, accessible to multiple users and organizations. While PaaS can be delivered via a public cloud, the term itself does not specify the service model focused on application development. Therefore, it lacks the specificity needed to answer the question correctly.

IaaS provides virtualized computing resources over the internet, allowing users to manage and control the underlying infrastructure, such as servers and storage. This model requires significant management effort from developers and does not meet the criteria of allowing them to focus solely on application development and deployment.