Why is it necessary to have usernames and passwords if one is working on a network?​

Which of the following is the definition of role-based access control ( rbac)? (a) ensures that data has not been accidentally or intentionally modified without authorization. (b) access control system where rights are assigned based on a user’s role rather than his or her identity. (c) ensures that private or sensitive information is not disclosed to unauthorized individuals. (d)the principle in which a subject—whether a user, an application, or another entity—should be given the minimum level of rights necessary to perform legitimate functions.