【单选题】

The passage suggests that an assumption underlying non-economist social scientists dismal of economics as dismal is that
A．(A) positive-sum outcomes cannot, by the definition of the power model, exist

B．(B) all social sciences founded on pragmatism instead of idealism are dismal
C．(C) zero-sum interactions models are inherently optimistic in their view of the future
D．(D) scarcity does not necessarily exist as a controlling factor in social systems
E．(E) economics is anti-utopian by nature, proposing a more realistic view of the future