21. Assume that a company that produces and sells tires expects to produce 16,000 tires in January, 18,000 tires in February, and 20,000 tires in March. Each tire requires 5 pounds of rubber. It wants to have an ending inventory at the end of each month equal to 10% of the number of pounds of rubber that it expects to use to make tires in the following month. How many pounds of rubber should the company purchase in February? A) 89,000 B) 90,000 C)91,000