As at 31 December 2018, ABC Limited ("ABC") had a net balance of accounts receivable of $9,000, representing a gross amount of $9,100 due from a customer, BBA Limited ("BBA), less the allowance for doubtful accounts of $100. Closing inventory of $3,000 was held as at 31 December 2018 (being 100 units at $30 each). Market value of the inventory was estimated to be well-above the costs. On 5 January 2019, ABC purchased 300 units of inventories at $32 each and paid by cash. On 10 January 2019, ABC sold 150 units of goods to BBA for a gross price of $6,000 in total. This was a credit sale with terms 2/10, n/30. ABC adopts gross method in accounting for cash discount. On 25 January 2019, ABC collected $15,100 from BBA for all the amounts due. Question For the month ended 31 January 2019, how much "cost of goods sold" shall be reported by if average costing is adopted by ABC? Select one: O A. $4,800 O B. $4,500 O C. $4,600 O D. $4,725