Answer:
A. Line 3
Step-by-step explanation:
First, lets order the query like this:
1 SELECT isbn, title
2 FROM books
3 WHERE pubid =
4 (SELECT pubid
5 FROM books
6 WHERE title = 'SHORTEST POEMS')
7 AND retail-cost >
8 (SELECT AVG(retail-cost)
9 FROM books);
It's not necessary to filter through the pubid to find the books with the title "SHORTEST POEMS". The query could be just like this:
SELECT isbn, title
FROM books
WHERE title = 'SHORTEST POEMS'
AND retail-cost >
(SELECT AVG(retail-cost)
FROM books);