What Is the Best Example of the Diminishing Product of Labour

What is the best example of the diminishing product of labour on an orchard?

A) when only a few workers are hired, they pick from only the best (most productive and accessible) trees in the orchard
B) as more workers are hired, the orchard might become crowded with fruit pickers
C) as more workers are hired, workers are required to pick from trees that have fewer fruit
D) all of the above are good explanations