27. Refer to Figure 6, which shows supply and demand in a perfectly competitive market. At a price of $30, the quantity, a) demanded exceeds the quantity supplied and there is upward pressure on prices because some consumers are willing to pay more than $30. b) demanded exceeds the quantity supplied and there is upward pressure on prices because some producers are willing to sell for less than $30. c) supplied exceeds the quantity demanded and there is upward pressure on prices because some consumers are willing to pay more than $30. d) supplied exceeds the quantity demanded and there is upward pressure on prices because some producers are willing to sell for less than $30