The correct answer is: A. back end
Back-end software is the software that runs behind the scenes to support the front-end software that users interact with. It is responsible for managing data, processing transactions, and communicating with other systems.
MS-Access and Oracle are both examples of back-end software. They are used to store and manage data, and to develop applications that run on a database.
Front-end software is the software that users interact with directly. It is responsible for presenting data to users in a way that is easy to understand and use.
Mathematical software is software that is used to perform mathematical calculations. It includes software for statistics, calculus, and other mathematical applications.
None of these is the correct answer.