Answer:
a. equal to his or her contribution to the productive process
Explanation:
Marginal productivity refers to the extra income incurred by increasing one unit of labor when all the other inputs are kept in constant. The theory of Marginal productivity was advocated by T.H. Von Thunen in 1826 who was a German economist. The price of the services This theory states that the price of all the production factor is equal to the marginal productivity under the perfect competition.