Which of the following is an example of a one-to-one relationship?

Supervisors and employees

Sales transactions and transaction numbers

Database files and databases

None of the above are examples of one-to-one relationships

A specific database field in Table 1 both serves as a unique identifier in Table 2 and is used to link both of the tables as a relational database. What is the correct term for this database field in Table 2?

A. Primary key

B. Foreign key

C. Both A and B

D. Neither A nor B