Ross purchases 3 cookbooks for $18.89 each, a set of measuring cups for $2.68, 4 kitchen utensils for $5.35 each and a cooling rack for $9.60. ross uses a promotional discount of $5 off on the purchase of 3 or more cookbooks. there are no taxes charged on his purchase, but shipping charges are based on the following table: amount of purchase standard shipping express shipping up to $50 $4.00 $7.00 $50 up to $100 $5.25 $9.50 $100 up to $200 $6.00 $12.75 $200 and over $8.50 $15.00 ross selects standard shipping and is billed $94.35 for the total of the online purchase. determine if ross has been billed correctly for his purchase. a. ross has been billed correctly. b. ross has not been charged enough for his purchase. c. ross has been over charged by $3.75 for his purchase. d. ross has been over charged by $4.25 for his purchase