Gross billings for merchandise sold by Cullumber Company to its customers last year amounted to $12720000; sales returns and allowances were $360000, sales discounts were $175300, and freight-out was $139400. Net sales last year for Cullumber Company were:____.a. $12,720,000.b. $12,275,000.c. $12,175,000.d. None of the above.