The correct answer is: B. a map of overall structure of a database.
A database
scheme is a logical description of the database, including the tables, columns, and relationships between them. It is used to define the structure of the database and to create the database objects.A relationship service bureau is a company that provides database management services to other companies.
A parent with no owners is a parent node in a hierarchical database that does not have any child nodes.
A two dimensional table is a table that has two dimensions, rows and columns.
None of the above is a correct answer to the question.