Hi, I wanna step by step calculation of this question please.

Powerpoint Company, a wholesaler of grain, has a sales budget for July of $300,000. Sales are expected to increase at a rate of 10% per month. The cost of grain is expected to be 40% of sales each month. All purchases are paid for in the month following purchase. The opening inventory (1St July) of grain is $10,000, and the desired closing inventory level is 10% of the amount required to meet the following months sales. The opening balance of accounts payable is $76,000. The cost of grains sold during July is expected to be: Select one: a. $132,000 O b. $76,000 O c. $120,000 O d. $123,200 The correct answer is: $120,000