Selected balance sheet information for the Wolf Company at November 30, and December 31, 2011, is presented below. The company uses the perpetual inventory system and all sales to customers are made on credit. Nov. 30 Dec. 31 Debits Credits Debits Credits Accounts receivable 10,000 3,000 Prepaid insurance 5,000 7,500 Inventory 7,000 6,000 Accounts payable 12,000 15,000 Wages payable 5,000 3,000 The following cash flow information also is available: a. Cash collected from credit customers$80,000. b. Cash paid for insurance$5,000. c. Cash paid to suppliers of inventory$60,000 (the entire accounts payable amounts relate to inventory purchases). d. Cash paid to employees for wages$10,000. Required: (1) Determine the following for the month of December. (Omit the "$" sign in your response.) a. Sales revenue $ b. Cost of goods sold $ c. Insurance expense $ d. Wage expense $