The correct answer is: A. a person.
A DBA (Database Administrator) is a person who is responsible for the design, implementation, maintenance, and security of a database. They typically have a strong understanding of database management systems (DBMS) and database design principles.
A computer device is a physical object that is used to process data. Examples of computer devices include computers, laptops, tablets, and smartphones.
A communication technique is a method of exchanging information between two or more people. Examples of communication techniques include speaking, writing, and using sign language.
Therefore, the DBA is a person, not a computer device or a communication technique.