a manager must make a decision on shipping. there are two shippers, a and b. both offer a two-day rate: a for $500 and b for $525. in addition, a offers a three-day rate of $455 and a nine-day rate of $400, and b offers a four-day rate of $445 and a seven-day rate of $410. annual holding costs are 35 percent of unit price. three hundred boxes are to be shipped, and each box has a price of $140. which shipping alternative would you recommend? explain.3