Answer:
revolution transformed economics that has been based on agriculture and handicrafts into economics based on large scale industry manufacturing and the factory system new machines new power new shoes and new waste organism industries for productive and efficient
Economy crash
or
economical crash
The correct answer is D, because "their" signifie that they are having "their" conversation, and that they own the conversation. C is incorrect because "there" describes where, B is incorrect because "they" describe who, and A is incorrect because "they are" doesn't grammatically or sensibly fit in, so the answer is D.
