Recall the Application About the Shutdown Price for Zinc to Answer

Recall the Application about the shutdown price for zinc to answer the following question(s) .
-Recall the Application. If the selling price of zinc falls below the shutdown price for half of the world's zinc mines, the output produced from these mines will

A) decrease by 50 percent.
B) still remain constant.
C) increase by 50 percent.
D) fall to zero.