To Find the Opportunity Cost of Producing One More Unit

To find the opportunity cost of producing one more unit of any product while on the production possibilities frontier requires

A) setting the amounts of the two products equal to each other.
B) setting the change in one product equal to the change in the other product.
C) dividing the amount of the product forgone by the amount of the product gained.
D) subtracting the change in the product whose production increased from the change in the product whose production decreased.
E) None of these describe how to find opportunity cost.