what is the difference between markup on cost and markup on retail? select one: a. markups on retail are subject to sales tax, markups on cost are not. b. markup on cost divides the gross margin by the retail, markup on retail divides the gross margin by the cost. c. as a percentage, for a given item, markup on retail is typically a higher percentage than markup on cost. d. retailers usually calculate markup on cost, manufacturers calculate markup on retail. e. markup on cost divides the gross margin by the cost, markup on retail divides the gross margin by the retail.