The diagram indicates that the production possibility frontier for maize and beans has shifted from PPF1 to PPF2. What change has occurred in the opportunity cost of maize and in the returns to factors producing beans?
- Aopportunity cost of maize fallen; returns to factors producing beans fallen
- Bopportunity cost of maize fallen; returns to factors producing beans risen
- Copportunity cost of maize risen; returns to factors producing beans fallen
- Dopportunity cost of maize risen; returns to factors producing beans risen