Answer:
a) all trades that can generate gains from trade take place, and no trades take place that would not generate gains from trade.
Step-by-step explanation:
When we draw the demand and supply curve, the point in the curve where both meet shows that the market is in a state of equilibrium.
The price is the equilibrium price and the quantity is the equilibrium quantity. Prices would become stable at this point. At this point every trade that would bring about gains from trade would take place. There would be no trade in the market equilibrium that would not generate gains from trade. This is because the market equilibrium is an optimum point for trade for either party, that is the buyer and the seller.