. Law of Variable Proportions is valid when
A: Only one input is varied and all other inputs are kept constant
B: All Factors are kept constant
C: All inputs are varied in the same proportion
D: Any of the above
- The law of variable proportions, an essential economic concept,
states that an increase in a particular factor of production,
while all others are constant, will cause the marginal product to eventually decline.
- The following diagram depicts the law of variable proportions:
Here, TPP is the abbreviation for the total physical product and MPP is the abbreviation for marginal physical product.
Hence, the correct answer is option A: Only one input is varied, and all other inputs are kept constant.