Question:
Sulfates are a key factor in all areas of the United States, particularly in the East, where high humidity increases the light extinction efficiency of sulfates.

Does it follow that "Sulfates influence mostly the East of the United States."?
Answer:
yes

Question:
He's took.

Does it follow that "He's very much available."?
Answer:
no

Question:
So how much did it sell for?

Does it follow that "The item was sold."?
Answer:
yes

Question:
Keep in mind the requirement that a subclass has to generate revenue to cover its costs.

Does it follow that "Subclasses spend months making money just to pay off initial costs."?
Answer:
it is not possible to tell