Which function should a Data Analyst use to aggregate total regional sales for a dataset...

FIXED is the Level of Detail scoping keyword designed to compute an aggregation using explicitly specified dimensions without reference to the dimensions currently present in the view. For regional totals, an expression such as {FIXED [Region] : SUM([Sales] )} calculates sales at the Region level even when the visualization includes additional dimensions such as State or Customer. INCLUDE adds a dimension to the view’s level of detail, while EXCLUDE removes specified view dimensions; both therefore depend on the view context. SUM by itself is a standard aggregate and operates at the current visualization level of detail. Because the requirement states that total regional sales must be calculated regardless of what is in the view, FIXED provides the necessary view-independent level of detail.