The slope of PPC depends upon marginal opportunity cost. a constant opportunity cost indicates that given resources are equally suited for the production of two goods. So when opportunity cost is constant, PPC curve is a straight line.

PPC Curve and Marginal Opportunity Cost

PPC Curve stands for Production Possibility Curve that shows the maximum combination of two goods that a country can produce with its available resources and technology. It is a graphical representation of the opportunity cost that a country has to pay to produce one unit of a good over the other.

Marginal Opportunity Cost is the cost of producing an additional unit of a good in terms of the foregone production of another good. It is the slope of the PPC Curve.

Shape of PPC Curve with Constant Marginal Opportunity Cost

When the Marginal Opportunity Cost is constant, the PPC Curve will be a straight line. It implies that the resources are equally efficient in producing both the goods.

For Example, if a country can produce 100 units of wheat and 50 units of rice with its available resources and technology, then the Marginal Opportunity Cost of producing an additional unit of wheat will be 0.5 units of rice. Similarly, the Marginal Opportunity Cost of producing an additional unit of rice will be 2 units of wheat.

Here, the Marginal Opportunity Cost of producing wheat is constant at 0.5 units of rice, and the Marginal Opportunity Cost of producing rice is constant at 2 units of wheat. Hence, the PPC Curve will be a straight line with a constant slope.

Conclusion

In conclusion, the shape of the PPC Curve depends on the Marginal Opportunity Cost. A constant Marginal Opportunity Cost implies that the resources are equally efficient in producing both the goods, and hence, the PPC Curve will be a straight line.

The correct option is 'D' because marginal opportunity cost is constant