It has to be Answer D
Due to good weather, there is a surplus in the market for an agricultural product.
Which change would cause the market to return to equilibrium?
Surplus - excess supply
A a decrease in demand would exacberate the surplus, hence A is incorrect.
B a fall in price would increase the demand, which would exacberate the surplus, hence B is incorrect.
C an increase in supply would exacberate the surplus, hence A is incorrect.
D a rise in price would reduce the demand, it is the correct answer.
An increase in price would result in reduction in demand and increase in supply, whereas a decrease in price would result in an increase in demand and decrease in supply.