A primary key is a composite key that was selected to be the main identifier for the relation.

Answer: Option A

Option1: True
- A primary key is a unique identifier for each record in a table. - It can be a single attribute or a combination of multiple attributes. - In the case of a composite key, it is a key that consists of more than one attribute to uniquely identify a record. - Therefore, a primary key can indeed be a composite key that serves as the main identifier for the relation.

Option2: False
- This statement is incorrect as explained above. - A primary key can be a composite key and is often used as the main identifier for a relation.

Conclusion:
- The correct option is True as a primary key can be a composite key that serves as the main identifier for a relation.