Beginning Ending raw materials inventory raw materials inventory $360 $230 $440 Direct labor $720 $360 Operating expenses Purchases of direct materials $420 $650 Beginning work in process inventory Ending work in process inventory $5,500 $810 Sales revenue Manufacturing overhead Beginning finished goods inventory Ending finished goods inventory $310 $280 What was operating income? A. $3,750 B. $3,240 O C. $4,680 O D. $5,500