the first part has been done. please explain how to do the second part part B and C. Thank you

the second picture is the A part and the first B pic is the B and C part

B. Shopco prefers to avoid backorders. As an alternative, Shopco would like to try using a Chase Method. Their current staffing levels have them able to produce 720 units per month using regular labour. They can work overtime one Saturday per month to produce an extra 50 units per day. Inventory holding costs are $25 per unit per month Overtime units are $125 each. Beginning inventory is 50 units. . Backorder costs are $40 per unit per month C. Compare the two plans in terms of their overall cost and the impact on their organization. What do suggest is the best course of action and why? (2) ShopCo makes shopping carts. Below is their forecast for the first 6 months next year. They want to cost out a level production plan of 720 units per month. Beginning Inventory is 50 units. Inventory holding costs are $25 per unit per month. Backorder costs are $40 per unit per month. Regular labour is $80 per unit