Jackson uses the first-in-first-out (FIFO) method for measuring inventories. Inventories in the balance sheet as at 1 January 2020 were measured at 560,000. During 2020 Jacksons total cost of production was 10,440,000. Jacksons closing inventory at 31 December 2020 on a FIFO basis was 980,000, however, finished goods included in inventories with a cost of 90,000 to produce have become obsolete, and are expected to be sold for only 30,000. The companys cost of sales for 2020 and ending inventory balance are:

and why?

a) 10,020,000 and 890,000 b) 10,080,000 and 920,000 c) 10,440,000 and 980,000 d) 10,110,000 and 910,000