To understand what session.createQuery("Query").scroll() returns, the user needs to have understanding of Hibernate, Java and SQL.

Explanation of each option:

A. ListResultSet: This option is incorrect because ListResultSet is not a valid class in Hibernate.

B. ResultSet: This option is incorrect because ResultSet is a class in Java that represents a table of data representing a database result set, and it is not returned by the scroll() method in Hibernate.

C. ScrollableResultSet: This option is incorrect because ScrollableResultSet is not a valid class in Hibernate.

D. ScrollableResult: This option is correct. The scroll() method in Hibernate returns a ScrollableResult object, which is used to traverse a result set. It provides methods to move the cursor forward and backward, as well as methods to retrieve the current row or a subset of rows.

Therefore, the answer is: D. ScrollableResult.