The answer to this question is d. Both (a) and (b) are possible.
Here's why:
A price ceiling is a government-imposed maximum price that can be charged for a good or service. It essentially sets a legal limit on how high the price can go.
When a price ceiling is set below the equilibrium price (the price where supply and demand naturally meet), it disrupts the market equilibrium.
In this scenario:
Quantity demanded will increase because the good or service is now artificially cheaper. Consumers who wouldn't have bought it at the higher equilibrium price will now be willing and able to do so.
Quantity supplied will decrease because producers are no longer able to receive the equilibrium price for their product. They may choose to produce less or even exit the market altogether.
This creates a disequilibrium where quantity demanded exceeds quantity supplied, leading to a shortage. This is scenario (a).
However, it's also possible for some suppliers to be willing to sell at the price ceiling, especially if they have fixed costs or face limited storage capacity. In this case, quantity demanded and quantity supplied could be equal, even though it's not the equilibrium level. This is scenario (c).
Therefore, both situations (a) and (c) are possible depending on the specific market conditions and how producers respond to the price ceiling.