You intend to use SQL Server 2008 to create a database solution. You are creating a database to support the office manager. The exhibit below shows the structure of the database.

The database you design must meet the requirements below:
* First, an employee can be given more than one task.
* Second, the task is deleted upon completion and when deleted, the associated assignment is deleted.
* Third, the employee link to the assignment is replaced with a NULL value when an employee is no longer available to complete a task.
So what should you do to implement these requirements to maintain data integrity?

A.
On the Employee, Task, and Assignment entities, DDL INSERT triggers should be created

B.
On the TaskID and EmployeeID attributes in the Assignment entity, CHECK constraints should becreated

C.
On the TaskID and EmployeeID attributes in the Task and Employee entities, foreign Keys constraintsshould be created respectively.You specify the appropriate On Delete action after the Assignment entity is referenced.

D.
On the TaskID and EmployeeID attributes in the Assignment entity, Foreign Keys constraints should be created.You specify the appropriate On Delete action. After the Task and Employee entities are referenced respectively.