If the marginal rate of transformation is constant throughout, the production Possibilities Frontier will be

Downward sloping and linear.

The correct answer is Option (3) → Downward sloping and linear.

The Production Possibilities Frontier (PPF) shows the various combinations of two goods that an economy can produce using all its resources efficiently.

• The Marginal Rate of Transformation (MRT) represents how much of one good must be given up to produce an additional unit of another good.

• When the MRT is constant, it means the opportunity cost remains the same as we move along the PPF.

• This happens when resources are perfectly substitutable between the production of the two goods.

Thus, the PPF will be a straight line (linear) sloping downward from left to right.