15. Wolfe, Inc., began operations on January 1 of the current year with a $12,000 cash balance. Forty percent of sales are collected in the month of sale; 60% are collected in the month following sale. Similarly, 20% of purchases are paid in the month of purchase, and 80% are paid in the month following purchase. The following data apply to January and February: January February Sales $35,000 $55,000 Purchases 30,000 40,000 Operating expenses 7,000 9,000 If operating expenses are paid in the month incurred and include monthly depreciation charges of $2,500, determine the change in Wolfe's cash balance during February. A. $2,000 increase. B. $4,500 increase. C. $5,000 increase. D. $7,500 increase