Answer:
d. diminishing marginal returns
Explanation:
Marginal return on work is a microeconomic concept that aims to measure the increase in the amount produced when an extra worker is hired.
When the fourth employee is contradicted, production increases by 6 units, ie the marginal return of the worker is 6 units. When the fifth employee is hired, production increases by 5 units. When the sixth employee is hired, the production increases by 3 units and when the seventh employee is hired, the production increases by one unit, thus the marginal return of this worker is 1 unit. This means that the productivity of each employee increases, but at a decreasing rate. In other words, marginal returns on production are decreasing from the fourth worker. Note that from the first to the second and from the second to the third marginal returns are increasing (6 and 7 respectively).