Respuesta :
primary key is a key which does not allow user to enter duplicate values
Answer:
The correct answer is letter "A": a field that uniquely identifies a record in a table.
Explanation:
A primary key is a unique relational database table that is created to identify record tables. Primary keys contain a special value for each row of data and it does not include "null" data. Typical information recorded in primary key tables are individual's telephone numbers, insurance policy numbers or bank account numbers.