1. What subtotals are generated by the clause GROUP BY ROLLUP (region, store)?
- Only a grand total.
- Groupings for (region, store), (region), and a grand total (NULL, NULL).
- Groupings for (region, store), (store), and (region).
- All combinations including (store).
Hint: ROLLUP calculates hierarchical subtotals, rolling up from right-to-left: first (region, store), then (region), then the grand total.