A single-valued path expression is when you use a cmp field name in your EJB QL. Contrast this to a range variable, which is an abstract schema name that you can refer to in your EBJ QL. Why is option a correct for question 17 on page 430 of HFEJB? This question refers to the use of IN by the WHERE clause. For example: Select m.title from MovieSchema m Where m.title IN ('The Shining', 'Appocalypse Now') Option a is correct because you must use the single quotes around the options you list in the IN clause.