A manufacturing company has beginning work in process inventory of $15,000 and ending work in process inventory of $20,000. During the period, direct materials used were $50,000, direct labor cost was $30,000, and manufacturing overhead incurred was $20,000. Calculate: 

a) The cost of goods manufactured. 

b) The total manufacturing costs incurred.

 c) The cost of goods sold.

 d) The gross profit.