Concept:Free and open source software (FOSS) are tools whose source code is open to the public and available at no cost.
Explanation:Among the given options, only LibreOffice and Mozilla Firefox are both free and open source software.
LibreOffice is a free office suite containing Writer, Calc, Impress, Draw, Base, and Math.
It supports formats like Microsoft Word, Excel, and PowerPoint, and its native format is Open Document Format (ODF).
Mozilla Firefox is a free and open source web browser developed by the Mozilla Foundation.
It works on Windows, macOS, Linux, Android, and iOS.
Firefox includes privacy features such as tracking protection and secure browsing.
Its source code is publicly accessible, allowing community contributions and transparency.
The other options are incorrect because Matlab, Adobe Acrobat, and Microsoft products are proprietary or not fully free.
Answer:LibreOffice and Mozilla Firefox are the popular free and open source software tools.
Therefore, the correct option is B: Libre Office, Mozilla Firefox.