What defines open source software?

Open source software is characterized by the fact that its source code is made available for public use. This means anyone can view, modify, and distribute the software, fostering a community-based approach to development and collaboration. The open nature of the source code encourages transparency, innovation, and sharing among developers, allowing users to not only use the software but also to adapt it to their needs.

This concept directly contrasts with proprietary software, where the source code is kept secret, and users have restrictions on how the software can be used or shared. Open source software often comes with licenses that comply with this model, promoting freedom and accessibility for users.

The other provided choices miss key elements of open source software. Software available for purchase does not imply that it is open source, as many commercial software products are proprietary. Limited access to source code suggests a lack of transparency and collaboration, which is not aligned with the principles of open source. Lastly, software intended only for educational purposes does not define open source, as such software may or may not have open access to its source code.