which column in the Employee table should you a create a unique constraint?

You administer a Microsoft SQL Server 2012 database. The database contains a table named Employee. Part
of the Employee table is shown in the exhibit. (Refer to the Exhibit.)


Confidential information about the employees is stored in a separate table named EmployeeData. One record
exists within EmployeeData for each record in the Employee table. You need to assign the appropriate
constraints and table properties to ensure data integrity and visibility. On which column in the Employee table
should you a create a unique constraint?

A.
DateHired

B.
DepartmentID

C.
EmployeelD

D.
EmployeeNum

E.
FirstName

F.
JobTitle

G.
LastName

H.
MiddleName

I.
ReportsToID

Explanation:
Verified answer as correct.