Alan buys a book that is on sale.
He writes the expression 0.7b to show the percent of the original cost of the book, b, that he pays.
He rewrites the expression as b minus three tenths b.
Which statement explains why Alan rewrites the expression?
A)He receives another discount on the book.
B)He buys another book with a different discount.
C)He wants to show by what percent the book was discounted.
D)He wants to show what percent of the original price he paid