I am unable to solve part B. I have include the solution to part A below

#3. Hartley Homes in North Texas is building a development in Northern Tarrant County and is currently negotiating with two flooring dealers on tile prices. Both dealers offer several competing tile families consisting of small (mosaic or 1 x 1), medium (4 x 4 or subway), and large (12 x 12 and 12 x 24) tiles. Each dealer represents a different tile manufacturer, but there is reasonable overlap in styles while still permitting nuanced differences for the discriminating buyer. Both tile manufacturers deal in the high-quality (\"pricey\") tile market. The dealers have offered Hartley Homes competing prices for each category of tile, but the prices are only good for 90 clays. To lock in these prices for the next 32 months, Hartley must sign a contract with each dealer committing to a certain minimum dollar amount for each tile category (small, medium, large}. Hartley wants to determine how many dollars to contractually guarantee each dealer to lock in these prices. Over the next 32 months, Hartley knows that they will need, at a minimu m, 40,000 totai SQFT of small tile, 60,000 total SQFT of medium tile, and 240,000 total SQFT of large tile. Additionally, Hartley knows that if they order large tile from a particular dealer, they will need to purchase at least 10% of this same square footage from the dealer's medium tile category to match designs. The prices offered per square foot are given in the table below. Prices (SISQFT) mm- mm \" krw A. Determine a minimum cost purchasing plan for Hartley. From that purchasing p an, etermlne r each category that Hartley can guarantee to each dealer. B. Suppose Dealer 2 offers a special incentive to encou rage purchases from all three of their tile categories. Dealer 2 will discount the f Hartley's three purchases by category spend (dollars for small, dollars for medium, and dollars for large) b).(l\\lote that if Hartley does not buy from all three categories, their discount is 0.) Incorporate this into your model, determine a new optimal purchase plan, and determine a dollar (spend) amount for each category that Hartley can guarantee to each dealer. Hint: You only need one new decision variable but three new constraints. Small Medium Large Dealer 1 13.00 $ 8.00 S 5.50 Dealer 2 S 12.00 S 10.00 S 6.00 D1S DIM DIL D2S D2M D2L Decision Varibales 60000 240000 40000 0 0 Cost Inputs S 13.00 8.00 5.50 $ 12.00 10.00 6.00 S S 480,000 S 1,320,000 $ 480,000 S S $ 2,280,000 LHS Type RHS Small 40000 >= 40000 Medium 1 1 60000 >= 60000 Large 1 1 240000 >= 240000 D1 10% Order Requirements' 1 -0.1 36000 >= D2 10% Order Requirements' -0.1 0 >= 0