You are developing a SQL Server 2008 Analysis Services (SSAS) solution which contains a
table called TestFact which includes two columns listed below for Company.com.
In order to develop a measure which gets the amount of customers who owns placed orders.

Which is the correct answer?

A.
You should configure the Usage attribute to Distinct count and the Source Column
attribute to OrderKey.

B.
You should configure the Usage attribute to Sum count and the Source Column attribute
to OrderKey.

C.
You should configure the Usage attribute to Distinct count and the Source Column
attribute to CustomerKey.

D.
You should configure the Usage attribute to Sum count and the Source Column attribute
to CustomerKey.