The following information was obtained from the books of the Greybo Company for the year. Opening balances: Raw materials inventory $20,000 WIP inventory $65,000 Finished goods $12,000 Closing balances: Raw materials inventory $10,000 WIP inventory $90,000 Finished goods $15,000 The company purchased raw[material inventory to the value of $90,000 Conversion costs of $80,000 were incurred during the year. The cost of goods sold during the year was: Select one: a. $87,000 b. None of the above c. $72,000 d. $152,000 e. $167,000