What defines a web application?

A web application is best defined as a website that allows interaction from any internet-connected device. This definition highlights the core characteristic of web applications, which is their accessibility through web browsers across various devices, including computers, tablets, and smartphones. Web applications rely on server-side processes and often utilize web technologies such as HTML, CSS, and JavaScript to create dynamic and interactive user experiences.

In contrast, the other options describe different types of software and platforms. A software that runs exclusively on a mobile device refers specifically to mobile applications, which are designed for smartphones and tablets but do not function as web applications. A software installed only on local machines pertains to desktop applications that require installation on a specific device and do not operate over the internet. Lastly, a platform requiring specific hardware for access suggests a limitation on device compatibility, which is contrary to the inclusive nature of web applications that function across various devices without special hardware requirements.