Ronaldo Corporation, a manufacturing company, has provided data concerning its operations for September. The beginning balance in the raw materials account was $39,000 and the ending balance was $28,000. Raw materials purchased during the month totaled $51,000. Manufacturing overhead cost incurred during the month was $92,000, of which $2,000 consisted of raw materials classified as indirect materials. The direct materials cost for September was: a. $57,000 b. $65,000 c. $60,000 d. $71,000 e. $63,000