When Marginal Product is constant?

The correct answer is Option (3) → Total Product is increasing at a constant rate.

• Marginal Product (MP) is the additional output produced by employing one more unit of a variable input (like labor). I.e. MP (L) = Change in Output/Change in Input

• If MP is constant, it means each additional unit of input adds the same amount to Total Product (TP).

For example, if MP = 5, then every additional unit of input increases TP by 5 units. This implies that TP increases at a constant rate, forming a straight upward-sloping line.