The correct answer is: D. join line
A join line is a line that connects related fields from two tables in the Relationship window. It is used to create a relationship between two tables, which allows you to join data from the two tables together.
A default field is a field that is automatically populated with a value when a new record is created.
A linking table is a table that contains a field that is common to two other tables. This field is used to create a relationship between the two tables.
An index is a data structure that is used to improve the performance of queries. It is created on a field or fields that are frequently used in queries.