A. in the long-run period
B. to large-scale enterprises
C. to small-scale enterprises
D. in the short-run period
Correct Answer:
Option A – in the long-run period
Explanation
The law of variable proportions states that as the quantity of one factor is increased, keeping the other factors fixed, the marginal product of that factor will eventually decline. It is applicable in the long-run period because only there are factors of production fixed.