Þ C. THE EQUALITY OPERATOR REQUIRES A SINGLE-ROW SUBQUERY, AND THE...

8. þ C. The equality operator requires a single-row subquery, and the

conditional subquery could return several rows.

ý A, B, and D. A is incorrect because the statement will fail in all

circumstances except the unlikely case where there is zero or one employee.

B is incorrect because this is not a problem; there need be no relationship

between the source of data for the inner and outer queries. D is incorrect

because the subquery will only run once; it is not a correlated subquery.