In the regression of textbook retail price (PRICE) on number of pages in the book (LENGTH), you estimate the following equation: PRICE = $10.40 + $0.03LENGTH What is the interpretation of the coefficient $0.03? Select one: a. As the estimated length of the book increases by one page, the price increases by $0.03. O b. As the length of the book increases by one page, the price increases by $0.03. O c. None of the interpretations are correct. O d. As the estimated length of the book increases by one page, the estimated price increases by $0.03. O e. As the length of the book increases by one page, the estimated price increases by $0.03 on average