A query in a database management system is a request for data or information from a database table or combination of tables. Its primary function is to retrieve specific information based on defined criteria.
Option C: Both A & B is correct because database queries, particularly those using SQL (Structured Query Language), are designed to select data from a single table when the required information resides in one place. More powerfully, they can also select and combine data from multiple tables using operations like JOINs, allowing for complex data retrieval across related datasets. Therefore, options A and B individually are only partially correct, as a query's utility extends to both scenarios, making C the most comprehensive and accurate answer.