What does the following expression do: "generate([Product line],topCount(descendants(currentMember([sales_and_marketing].[Products].[Products]),[sales_and_marketing].[Products].[Products].[Product]),2,[Revenue]))"?
A. Returns the top two products by revenue for each product line.
B. Finds the top two members by revenue at the product level and returns their respective ancestors at the product line level.
C. Calculates the top two product lines for each product.
D. Goes two levels up from products and returns the top members by revenue at that level.