Refer to the Above Graph, Which Shows the Market for Beef

Refer to the above graph, which shows the market for beef where demand shifted from D₁ and D₂. The change in equilibrium from E₁ to E₂ cannot be a result of:

A) Buyers expectations of lower prices for beef in the very near future
B) An increase in the subsidy given to cattle farms
C) A widespread concern about mad-cow disease
D) A decrease in the productivity of cattle farms