Concept:The law of variable proportions describes how output changes when one input is increased while others are fixed.
Explanation:When more units of a variable factor, such as labour, are added to fixed factors, the marginal product of that factor eventually declines.
This principle is commonly referred to in economics as the law of diminishing returns.
It does not describe demand, utility, or the effect of scaling all inputs together.
Therefore, among the given options, the correct equivalent name is the law of diminishing returns.
Answer:B. law of diminishing returns