The human resources office has informed staff that the vision care costs have increased from $39.95 to $50.95 payable by the end of the month. There are 120 staff in the department. If 50% of staff have already paid the increase in premium, how much money must be collected by the end of the month? Round the answer to the nearest whole number. a. $660, b. $1,320, c. $1,980, d. $3,057