Tableau practice: Multi-dimensional views and granularity

When you drop both Region (4 values) and Segment (3 values) onto the Rows shelf, what does Tableau display?

Create a cross-tab matrix comparing Region and Segment. Place Region on Rows, Segment on Columns, and SUM(Sales) on Columns.

A view has Category (3 values) on Rows and Segment (3 values) on Columns, with SUM(Sales). How many marks are rendered?

Build a nested view showing total Sales broken down by Region and Category. Place both Region and Category on Rows, and SUM(Sales) on Columns.

Build a view displaying total Units by Segment on Rows and SUM(Units) on Columns.