The answer to question 1 should be "None of the above." By definition, a correlated subquery is a subquery. Since none of the answers applies to ALL subqueries, there is no valid answer to question 1.
You also missed another case where subqueries can return multiple rows with a single column: on the right side of a conditional expression when used with the keyword SOME, ANY, or ALL.
Drew
J. Drew Allen
Business Intelligence Analyst
Philadelphia, PA