17. In the above figure, the most efficient way to produce 10 units is to hire A) 1 worker. B) 2 workers. C) 3 workers. D) 5 workers. 18. The table above gives costs at Jan's shirts Shop. Unfortunately, Jan's record keeping has been spotty. Each worker is paid $25 a day. Labor costs are the only variable costs of production. What is the total cost of producing 13 shirts? What is the total fixed cost of producing 10 shirts? What is the total variable cost of producing 4 shirts