Answer:
The correct answer is letter "C": be a straight line.
Step-by-step explanation:
The Production Possibility Frontier (PPF) aims to determine what the maximum production would be using finite factors. Typically, the higher production of a good implies lowering the production of another. The PPF is represented by a graph with a vertical "X" axis and a horizontal "Y" axis for easiness in understanding.
Thus, if the factors for production were perfectly adaptable, the PPF curve will display a straight line in a graph.