Which of the following is a model where software is delivered over the internet as a service?

The model where software is delivered over the internet as a service is Software as a Service (SaaS). This approach allows users to access applications via the internet without needing to install and maintain the software on their own devices. Users typically interact with SaaS applications through a web browser, which means they can use the software from anywhere with an internet connection. This model offers advantages such as ease of access, lower upfront costs, automatic updates, and scalability, as users can adjust their level of service based on their needs.

In contrast, Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet but does not offer software applications directly. Platform as a Service (PaaS) provides a platform for developers to build and manage applications without dealing with the underlying infrastructure but again does not deliver software for end-users. On-Premises refers to software that is installed and runs on local servers or individual computers, which contrasts with the cloud-based SaaS model. Thus, SaaS is specifically characterized by its delivery of software as a service over the internet.