As a Developer, why should you assign security to roles instead of users when setting up security on a site?

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As a Developer, why should you assign security to roles instead of users when setting up security on a site?

A. Security can be managed more efficiently as the rights and permissions apply to a group of users.
B. Role-based security allows multiple users to have the same username but different passwords.
C. Assigning security to roles enables individual rights and permissions to be configured by users.
D. Individual users with a role can set their own item security permissions.