Which of the following is not a relational database?

dBase (or dBASE) was one of the first database management systems for microcomputers day. The dBase system includes the core database engine, a query system, a forms engine, and a programming language that ties all of these components together.

4D is a relational database management system and IDE developed by Laurent Ribardière.

FoxPro was a text-based procedurally oriented programming language and database management system (DBMS), and it is also an object-oriented programming language.

Borland Reflex is a flat-file database management system for DOS.