A is false, because the main phrase does not narrow down the statement to firms only. B is false, because the main phrase does not imply anything about fairness. C is false, because the main phrase does not make any distinction between rich people and poor people. D is true , because it says the same thing as the main phrase, but also points out scarcity of resources as the main factor which forces us to make decisions. If resources were unlimited, there would be no need to make this decision.
The best answer is D because it accurately reflects the economic principle of scarcity and the necessity for economies to decide how to allocate limited resources. The other options either narrow the focus too much, address fairness without production, or imply wealth biases. Option D fully encompasses the decision-making process regarding production in all economies.
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