Dorina Company makes cases of canned dog food in batches of $1,000$ cases and sells each case for $$15.$ The plant capacity is $50,000$ cases; the company currently makes $40,000$ cases. Doggie$-$Mart has offered to buy $1,500$ cases for $$12$ per case. Because product$-$level and facility$-$level costs are unaffected by a special order, they are omitted.