4. Which of the following is a true statement about sales mix?a. Pro?ts will remain constant with an increase in total dollars of sales if the total sales in units remains constant. b. Pro?ts may decline with an increase in total dollars of sales if the sales mix shifts to sell more of the lowercontribution margin product. c. Pro?ts may decline with an increase in total dollars of sales if the sales mix shifts to sell more of the highcontribution margin product. d. Pro?ts will remain constant with a decrease in total dollars of sales if the sales mix also remains constant.