You need to redesign the dimension to enable the full historical reporting of changes to multiple student attributes including ParentOccupation

You are reviewing the design of a student dimension table in an existing data warehouse
hosted on SQL Azure.
The current dimension design does not allow the retention of historical changes to student
attributes such as ParentOccupation.
You need to redesign the dimension to enable the full historical reporting of changes to
multiple student attributes including ParentOccupation.
What should you do?

A.
Add CurrentValue and PreviousValue columns to the student dimension.

B.
Enable Snapshot Isolation on the data warehouse.

C.
Add an IsCurrent column to the student dimension.

D.
Add StartDate and EndDate columns to the student dimension.

Explanation:
Adding a start and end date will give you this ability as when a record is inserted and given a
start and end date, you’ll have the ability to determine when they were active therefore giving
you a retention of historical changes