Answer: C. The marginal cost curve shifts downward.
Explanation:
The level of productivity increasing means that the company is now goods per input which means that they are now more efficient at producing goods and services.
More efficiency in a company will mean that the company is spending less per input so its costs will reflect this. With marginal cost showing the effect per additional unit, this reduction in cost will be reflected by a shift downward in the Marginal cost curve.
