In the short run for a particular market, there are 300 firms. Each firm has a marginal cost of $30 when it produces 200 units of output. $30 is above every firm's average variable cost. One point on the market supply curve is
a.quantity = 60,000; price = $30.
b.quantity = 600,000; price = $90,000.
c.quantity = 300; price = $30.
d.quantity = 100,000; price = $30.