Selected data concerning the past year's operations of the Burner Corporation are as follows: Selling and administrative expenses $225,000 Direct materials used 397,500 Direct labor 450,000 Inventories Dec. 1 Dec. 31 Direct materials $36,000 $42,000 Work in process 75,000 84,000 Finished goods 69,000 57,000 The cost of direct materials purchased is: 

a. $403,500. 

b. $405,000. 

c. $367,500. 

d. $397,500.