You run a small health food shop. You sell 900 water purifying urns each year. The total cost of placing an order is $250 and it costs $75 per year to keep an urn on the inventory. What is the optimal order size and how many orders should you place per year?

a.77 urns per order; 12 orders per year.

b.600 urns per order; 1.5 orders per year.

c.40 urns per order; 23 orders per year.

d.86 urns per order; 10 orders per year.

e.900 urns per order; 1 order per year.