How Did the EPA Demonstrate the Danger of Coal Plants

How did the EPA demonstrate the danger of coal plants and justify its new rules?

A) It calculated the amount of preventable deaths and ailments as a result of coal plants and placed an economic value on the avoidance of these.
B) It calculated the amount of greenhouse gas emissions these plants were producing and convinced policy makers and the public that new rules and regulations would drastically curb these emissions.
C) It did not need to justify the new rules, as there was little to no resistance against them.
D) It exposed dangerous and rampant safety violations at coal plants, which was enough to shift public opinion in favor of the new rules.