Which of the following frameworks is specifically designated for mobile applications?

The Android framework is specifically designed for developing mobile applications on the Android operating system. It provides a comprehensive set of tools, libraries, and APIs that allow developers to create applications that can run efficiently on mobile devices. This framework facilitates access to device features such as GPS, camera, and sensors, as well as providing user interface components designed for touch input, making it ideal for mobile app development.

In contrast, the other frameworks mentioned serve different purposes. The Spring framework is primarily used for building enterprise-level applications and is primarily targeted at server-side development in Java. Ruby on Rails is a web application framework for building applications using the Ruby programming language, predominantly aimed at web development rather than mobile. Django, built on Python, is also a web framework and is not focused on mobile app development.

Thus, the Android framework stands out as the correct choice for its specific application in mobile environments, aligning precisely with the needs and functionalities required for developing mobile applications.