How should you complete the statements?

HOTSPOT
You have tables with the following requirements:
• Some records in the table named OrderLines do not exist in the table named Order.
• The column named OrderNumber must be a unique value in the Order table.
• The OrderNumber column on the OrderLines table allows null values.
• The OrderNumber column on the OrderLines table must be validated with the Order table.
• Must not allow a new record in the OrderLines table that does not match a record in the Order table.
How should you complete the statements? To answer, select the appropriate transact-SQL segments from the drop-down menus in the answer area.
NOTE: Each correct selection is worth one point.
Hot Area:

Correct Answer:

Explanation/Reference:
Explanation:
Box 1: PRIMARY KEY
Box 2: NOCHECK
Need NOCHECK as some records in the table named OrderLines do not exist in the table named Order.
Box 3: FOREIGN KEY
FOREIGN KEY allows inserting NULL values if there is no NOT NULL constraint defined on this key, but the PRIMARY KEY does not accept NULLs.
References:
https://www.sqlshack.com/commonly-used-sql-server-constraints-foreign-key-check-default/