An access control system that grants users only those rights necessary for them to perform their work is operating on which security principle?
a. discretionary access
b. least privilege
c. mandatory access

B. Least privilege                

Explanation:

The principle of least privilege an important principle in computer security. It limits the access rights for users and only grant them with the rights that are sufficient for them to perform their required task. For example a user is granted privilege to execute a file or manipulate data or use only the resources that are required for them to perform a particular task. This principle can be used only to limit and control access rights to system resources and applications.The least privilege is beneficial as it reduces the risk of unauthorized access.For example a user whose task is data entry and has nothing to do with controlling access or granting access rights to users, will only be allowed to enter data to the DB by the principle of least privilege.