You need to ensure that the Merge Join transformation works correctly without additional transformations

You are developing a data flow transformation to merge two data sources. One source
contains product data and the other source contains data about the country in which the
product was manufactured. Both data sources contain a two-character CountryCode column
and both use SQL Server. Both data sources contain an ORDER BY clause to sort the data
by the CountryCode column in ascending order.
You use a Merge Join transformation to join the data.

You need to ensure that the Merge Join transformation works correctly without additional
transformations. What should you do? (Each answer presents a part of the solution. Choose
all that apply.)

A.
set the appropriate SortKeyPosition properties on the data sources.

B.
set the ValidateExternalMetaData property on the Merge Join transformation to True.

C.
set the IsSorted property on both data sources.

D.
Set the MaxBuffersPerlnput property on the Merge Join transformation to 2.

Explanation:
References:
http://msdn.microsoft.com/en-us/library/ms141775.aspx
http://msdn.microsoft.com/en-us/library/ms137653.aspx
http://siddhumehta.blogspot.com/2009/05/validateexternalmetadata-property.html
http://msdn.microsoft.com/en-us/library/ms135950.aspx