12. Crazy Tubb Thumpers uses a level plan to produce its snowshoe covers. Beginning inventory for January is zero. Demand for covers in January, February, and March is as follows:

Month Demand January 5,000 February 0 March 20,000

a. Graph cumulative production for a level operations plan of 10,000 units per month. Show cumulative demand for the months January through March and indicate the ending inventory for March.