Everything else held constant, if aggregate output is to the ________ of the IS curve, then there is an excess demand of goods which will cause aggregate output to ________

Refer to the scenario above. If the government enforces a ban on Firm B, and asks Firm A to carry out all the production:

A) Firm A's marginal cost is likely to decrease, but its average cost is likely to increase. B) Firm A's marginal cost and average cost are likely to decrease. C) Firm A's marginal cost is likely to increase, but its average cost is likely to decrease. D) Firm A's marginal cost and average cost are likely to increase.

Refer to the figures below to answer this question:

Cap-and-trade versus emissions fee when marginal social benefits are inelastic and costs are
uncertain:

Cap-and-trade versus emissions fee when marginal social benefits are elastic and costs are uncertain:
a) In case of an inelastic marginal social benefit curve, what type of pollution reduction system should the government employ? Why?
b) If the social benefit curve is elastic, do you answer change?
c) What are advantages and disadvantages of Cap-and-Trade systems over Emission Fee
systems when the inflation and change in marginal costs are considered?