Answer:the quantities of some factors of production are fixed; the quantities of all factors of production can be varied - D
Explanation:
In the short run, some factors of production are fixed, which is usually the capital. Therefore for a company to increase output, it would need employ more workers, but would not increase capital.
Therefore in the short run, we can get diminishing marginal returns, which may cause marginal costs to start increasing quickly.
Also, in the short run, prices and wages fall out of equilibrium because a sudden rise in demand may lead to higher prices, and companies may not have the the capacity to respond and increase supply.
Long run
In the long run, usually greater than 6 months, all main factors of production are variable. The company has time to build a bigger one making it respond to changes in demand which means that a sudden rise in demand, would have a complimentary increase in supply to meet the demands and prices can be adjusted.
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