Temperatures Have Persisted Below Freezing Levels in Florida Throughout the Months

Temperatures have persisted below freezing levels in Florida throughout the months of December and January. As a result, demand for electricity sharply increased and the price of electricity rose sharply. The price of coal also rose. In these circumstances, any resulting shifts in the supply curves for coal miners and electricity producers

A) will determine what price to produce at given the market demand.
B) at all levels of output shifts marginal costs to the right.
C) can also be interpreted as shifts of their respective marginal cost curves.
D) shifts marginal costs to the right enabling both to produce more at any given market price.