According to Codd's rules, a relational DBMS must:

According to Codd's rules, a relational DBMS must:

• A. Reject any SQL support
• B. Support relational model properties and constraints
• C. Be non-relational by design
• D. Operate exclusively on local data

Answer: (B)

Codd's rules define what makes a system truly relational: it must implement the relational model's properties and enforce integrity constraints that keep data accurate and consistent. The statement that a relational DBMS must support relational model properties and constraints reflects this idea—data is organized into relations (tables) with rows and columns, and the system enforces keys, domain types, and integrity rules to maintain valid relationships and data validity. This foundation enables the use of a relational language to query and manipulate data while relying on the DBMS to preserve consistency and data independence. Saying that the system rejects SQL, is non-relational by design, or operates only on local data conflicts with the core relational principles, which emphasize a compliant data model and the ability to enforce constraints across potentially distributed data.

Codd's rules define what makes a system truly relational: it must implement the relational model's properties and enforce integrity constraints that keep data accurate and consistent. The statement that a relational DBMS must support relational model properties and constraints reflects this idea—data is organized into relations (tables) with rows and columns, and the system enforces keys, domain types, and integrity rules to maintain valid relationships and data validity. This foundation enables the use of a relational language to query and manipulate data while relying on the DBMS to preserve consistency and data independence. Saying that the system rejects SQL, is non-relational by design, or operates only on local data conflicts with the core relational principles, which emphasize a compliant data model and the ability to enforce constraints across potentially distributed data.