Your local bakery charges $6.00 for one dozen of doughnuts. if you purchase any number over 1 dozen you will only have to pay $0.40 per doughnut .the total cost of any number is given by the expression below 6+.40(d-12) which part of the expression represent the number of doughnuts purchased at the discounted rate a.(d-12) b..40(d-12) c. d d.6