Correct Option: B

Marginal product of an input (factor of production) is the extra output that can be produced by using one more unit of the input (for instance, the difference in output when a firm’s labor usage is increased from five to six units), assuming that the quantities of no other inputs to production change. Marginal product, which occasionally goes by the alias marginal physical product (MPP), is one of two measures derived from total product. The other is average product. Marginal product is directly proportional to total product.