Question * DS Q.1. 14*5 = 20Marks author(author_id, firstname, lastname) author_pub(author_id, pub_id, author_position) book(book_id, book_title, month, year, editon) pub(pub_id, title, book_id) Hint: Assume Keys(PK,FK) for each relation, accordingly. 1.1. Write a relational algebra expression: How many authors are not book editors. 1.2. Write a relational algebra expression that returns the names of all authors who are book editors. 1.3. Write a relational algebra expression that returns the names of all authors who are not book editors. 1.4. Write a relational algebra expression: Which authors authored a pub that was published in July