Which one of the following is TRUE?

Methods in an Object Class Diagram become methods in a relational database.

Attributes in a conceptual data model become columns in a relational database.

A many$-$to$-$many relationship in a conceptual data model will be implemented as a many$-$to$-$many relationship in a relational database.

A composite primary key must become a single$-$field primary key in a relational database.

None of the others is TRUE.