The price of fresh fish rose and the quantity sold fell. Other things remaining the same, which of the following is consistent with this observation?

A) The number of consumers that have a preference for fish increased.

B) The price of meat, which is a substitute for fish, rose.

C) The fishermen learned to fish more efficiently.

D) The cost of fishing increased.

E) The supply of fresh fish increased.

The correct answer is option D.

Explanation:

An increase in the cost of fishing will lead to a decrease in the supply of fishes. This happens because the suppliers will be able to supply less at the same cost.

So the supply curve will move to the left. This leftward shift in the supply curve will cause the equilibrium price to increase and the equilibrium quantity to decrease.

All the other options would have caused the equilibrium quantity to increase either through increased demand or increased supply.