Choice "A" is correct. I, III, and IV are correct. A database administrator controls the database, not the data, and duties generally include design of the firm's database, maintaining security measures, and controlling data structure.
Choices "b", "d", and "c" are incorrect. Item II is not correct because it refers to the definition and control of the data in the data dictionary. The data is the responsibility of the data administrator. A database administrator is responsible for the actual database software, while a data administrator is responsible for the definition, planning, and control of the data within a database or databases. The function of a database administrator is more technical, and the function of a data administrator is more administrative.