Paul the Publisher is thinking about publishing a new textbook on Microeconomics by Edwina Economist.The costs of supplying the book are a cost of $10 to print each copy of the book, a cost to distribute the book to bookstores of $1 for each copy, and then for each copy sold Edwina must be paid $5.Suppose Paul has printed 1000 copies of the book and distributed 500 to bookstores.Now he must decide whether to distribute the remaining 500 copies.If the remaining books are distributed then Paul expects all will be sold.What is the opportunity cost of choosing to distribute the remaining copies of the book?