The following information is available for the first month of operations for Bluemoon, Inc.: Sales $900,000 Gross profit 430,000 Indirect labor 35,000 Indirect materials 14,000 Other factory overhead 9,000 Materials purchased 360,000 Total manufacturing costs 670,000 Materials inventory, end of period 20,000 Based on the information provided for Bluemoon, Inc., calculate the cost of goods sold. a. $390,000 b. $500,000 c. $640,000 d. $470,000