Why do you recommend the virtual data mart layer? Note: There are 2 correct answers to this question.

Why do you recommend the virtual data mart layer? Note: There are 2 correct answers to this question.
A . To build an interface for queries and reports
B . To combine different InfoProviders using Join operations or Union operations
C . To combine centrally managed data with local files
D . To build corporate memory for reconstructions

Answer: A,B