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. (Click the Exhibit button.)

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