An electronic store sells 3,000 HD TV sets every quarter of the year. Each TV set costs the store $ 270.00. The carrying cost is set at 2% of the purchase price per unit per year. Each time an order is placed it costs the store $ 120.00 The supplier charges $10 for delivery of each order. Calculate:

a. Optimal order quantity.
b. Number of orders per year.
c. The supplier is willing to give a discount of 3% on the price of each set if the manager of the store orders 3,000 sets at a time. Should the manager accept the offer?