
Answer: 3 units of labor
Explanation:
Diminishing Marginal Returns refers to a scenario where less marginal output is recorded as more inputs are invested.
From the exhibit, that point would be at 3 units of labor.
At 0 units of labor, 0 units of output was recorded.
At 1 unit of labor, 50 units of output was produced. This means 50 more units were produced.
At 2 units of labor, 110 units of output were produced. This means 60 more units were produced.
At 3 units of labor, 155 units of output were produced meaning that only 45 more units were produced as a result of the extra unit of labor.
This 45 units is less than the 60 units that adding the second unit of labor added to production meaning less marginal output was recorded as more inputs were invested starting here.