The bookstore at State University orders copies of a textbook on quantitative analysis for $50 and then sells the texts to unsuspecting students for $250 each. A few weeks after the semester begins, the bookstore must return any unsold books to the publisher, who pays it $25 for each copy. Demand is strong for the quantitative analysis course, with class enrollment normally distributed with a mean of 200 and a standard deviation of 25. How many copies of the book should the bookstore order each semester? a. 231 b. 200 c. 217 d. 184