How to solve this question

Price Quantity demanded (dollars per CD) (CDs per week) 8.00 30,000 8:50 25,000 9.00 20,000 9.50 15,000 10.00 10,000 Quantity Marginal cost (CDs per week) (dollars per CD) 50 8.50 100 9.00 150 9.50 200 10.00 250 10.20 The first table shows the market demand schedule for CDs, and th second table shows the cost structure of each firm. The CD market is perfectly competitive and there are 100 identical firms. The market price of a CD is and CDs are produced and sold. A) $9.00; 20,000 B) $9.50; 15,000 C) $10.00; 10,000 D) $8.50; 24,000