please include work, i would like to understand. thank you!

Case Manufacturing expects to have 40,000 pounds of raw materials inventory on hand on June 30, the end of the current year. The company has budgeted the following production for the first four months of the coming year: July 100,000 August 120,000 September 150,000 October 110,000 Production (units) Case Manufacturing desires each month's ending raw materials inventory to be 20% of the following month's production needs. A finished unit requires two pounds of raw materials. Case Manufacturing's budgeted purchases of materials for September is: Multiple Choice 300,000 pounds 60.000 pounds 248,000 pounds 228,000 pounds 284.000 pounds