Answer:
The correct answer is option c.
Explanation:
A production possibilities frontier shows the maximum possible combination of two goods that can be produced using the given resources. The resources are scarce. So in order to increase the production of one good we need to decrease the production of the other.
Because of increasing opportunity cost, the production possibility curve is concave to the origin. When the opportunity cost or the rate of the trade-off between the two goods is constant the production possibility frontier will be a straight line.