Which statement is true regarding the ROLLUP operator specified in the GROUP BY clause
of a SQL statement?
A.
It produces higher-level subtotals, moving from right to left through the list of grouping
columns specified in the GROUP BY clause.
B.
It produces higher-level subtotals, moving in all the directions through the list of grouping
columns specified in the GROUP BY clause.
C.
It produces only the subtotals for the groups specified in the GROUP BY clause.
D.
It produces only the grand totals for the groups specified in the GROUP BY clause.