Reference: Ref 4-8 (Figure: Demand and Supply) Refer to the figure. Which statement is TRUE? Question 39 options: a) A free market is likely to produce less than 12 units of output. b) At 16 units of output, there are unexploited gains from trade. c) Buyers are willing to pay $20 for the 16th unit of output and it costs sellers $60 to produce that unit. d) The gains from trade are maximized at 20 units of output