Which of the following describes limitations or restrictions with regards to foreign key constraints for this scenario?

You work as a developer at ABC.com. The ABC.com network consists of a single domain named
ABC.com.
ABC.com has an existing SQL Server 2012 database that has multiple tables. You have been
instructed to create a foreign key relationship between two ABC.com tables.

Which of the following describes limitations or restrictions with regards to foreign key constraints
for this scenario? (Choose all that apply.)

A.
In a foreign key relationship, the foreign key constraint must only be connected to a primary key
constraint in another table.

B.
In a foreign key relationship, the foreign key constraint can reference only tables within the
same database on the same server.

C.
In a foreign key relationship, the foreign key constraint can be defined to reference the columns
of a UNIQUE constraint in another table.

D.
In a foreign key relationship, the foreign key constraint cannot reference another column in the
same table.

Explanation: