Diminishing marginal productivity can occur due to the following reason(s) ​

A) ​the difficulty of monitoring and motivating larger workforces
B) the increasing complexity of larger systems
C) the "fixity" or permanence of some factor of production
D) ​all of the above

Marginal Productivity

The additional output that can be produced by adding one more unit of a specific input, keeping all other inputs constant.

Fixity

In economics, refers to the inelasticity or immobility of certain factors, like land or capital, which can limit responsiveness to changes in market conditions.