What do you call a primary key field included in another table?

The correct answer is: A. Foreign key

A foreign key is a column or combination of columns in a table that refers to the primary key of another table. It is used to establish a relationship between two tables.

For example, in a table of customers, the customer ID column could be a foreign key that refers to the primary key of the table of orders. This would allow you to see which orders were placed by each customer.

A parent key is a primary key in a parent table. A child key is a foreign key in a child table. An index is a data structure that improves the performance of queries on a table.

I hope this helps! Let me know if you have any other questions.