Concept:A relational database is the type of database that links records across multiple files using shared fields or keys.
Explanation:In a relational database, data is stored in separate tables or files.
Each table contains rows and columns representing records and attributes.
A common data element, such as an ID number, appears in more than one table.
This common element acts as a key field that creates a relationship between the tables.
For example, a student file and a course file can be connected by the student ID field.
This allows data to be joined or retrieved together without duplicating the actual data.
A network database also links records, but it uses multiple parent-child links rather than shared key fields.
A hierarchical database connects records in a tree structure with one parent per child.
An object-oriented database stores data as objects, not as files with key fields.
Therefore, the correct description matches the relational model.
Answer:A. Relational database