Which of the following statements is correct?
a. The IN comparison operator can’t be usedwith a subquery that returns only one row of results.
b. The equals (=) comparison operator can’t be used with a subquery that returns more than one row of results.
c. In an uncorrelated subquery, statements in the outer query are executed first, and then statements in the subquery are executed.
d. A subquery can be nested only in the outer query’s SELECT clause.