You are defining a named set by using Multidimensional Expressions (MDX) in a sales cube. The cube includes a Product dimension that contains a Category hierarchy and a Color attribute hierarchy…

Option A likely uses incorrect syntax or a function that does not properly traverse the attribute relationship between the Category and Color hierarchies, producing incorrect or empty results.

Option B likely filters at the wrong granularity or uses a method that fails when Category members are associated with multiple colors, returning incorrect members.

The correct MDX expression uses EXISTS or FILTER to intersect Category hierarchy members with those linked to the Blue member of the Color attribute hierarchy, respecting the attribute relationship defined in the dimension. This approach returns only Category members that have at least one associated blue product, which is the standard and most performant MDX pattern for cross-attribute set filtering.

Option D likely uses a scalar function or non-set expression that cannot be used as a named set definition, or returns all Category members rather than filtering by color.