To set a field as the primary key, which button should be clicked after selecting the field?

To designate a field as the primary key in a database management system like Microsoft Access, the appropriate action involves utilizing a specific function within the table design interface. Clicking the Primary Key Button clearly indicates that the selected field will serve as the main identifier for records in that table. The primary key must contain unique values and cannot be null, which reinforces its role in maintaining data integrity and establishing relationships between tables.

The other options do not fulfill the requirement for setting a primary key. The Save Button merely saves any changes made to the structure but does not designate a primary key. The Design View Button is used to access the design layout of the table, but it does not set any properties by itself. The Lookup Wizard Button is a feature for creating a lookup field that helps in choosing values from another table or list, which is unrelated to defining the primary key.