The Marginal Product of Labor $$M P _ { L }$$

The marginal product of labor ( $$M P _ { L }$$ ) is the increase in total output associated with a

A) one unit increase in the quantity of labor,while holding the quantity of capital and technology constant.
B) one unit increase in the quantity of labor,while also increasing the quantity of capital by one unit and technology constant.
C) one unit increase in the quantity of labor,while also increasing the quantity of capital and technology by the same proportion.
D) one dollar increase in the price of labor,while holding the price of capital constant.