C. Let the database assign a unique number in a new field
Answer:
Option C is the correct answer to the following question.
Explanation:
In the following option is true because when once the entering of the fields name is done and you didn't choose any of the fields as primary but you want to choose field as primary and you also not choose any field as unique then, you should do one thing, you have to assign a unique number in your database in a new field.
