Which of the following characteristics pertaining to databases is NOT true?

A.
A data model should exist and all entities should have a significant name.

B.
Justifications must exist for normalized data.

C.
No NULLs should be allowed for primary keys.

D.
All relations must have a specific cardinality.

Explanation:
Data normalization is the process of reducing data to its canonical form. Database normalization is the process
of organizing the fields and tables of a relational database to minimize redundancy and dependency.
Justification is not a term that is used for normalized data.
Incorrect Answers:
A: A database model, such as a relational database model, is a type of data model that determines the logical
structure of a database and fundamentally determines in which manner data can be stored, organized, and
manipulated. Within a database model the entities must be named properly.
C: A primary key cannot have a NULL value.
D: A database relation could be either one-to-one, one-to-many, or many-to-many.

https://en.wikipedia.org/wiki/Data_normalization