In the income tax apportionment formula, market-sourcing the sales factor means that: a. Sales are sourced to the state(s) where the customer will use the product, i.e., to the customers markets. b. Sales are sourced to the state of the sellers corporate headquarters, i.e., where the marketing department works. c. Sales are sourced to the state of the customer. d. Sales are sourced to the state of the seller.