Bearings purchased from a renowned bearing manufacturer cost $65 each, and the forecast for next year's demand is 1000 units. If cost $25 every time an order is placed for more units, and the storage cost is $20 per unit per year.

a. What quantity should be ordered in each time?

b. What is the total ordering cost for a year?

c. What is the total storage cost for a year?

d. What is the total annual cost?