It can be inferred that the author of the passage believes each of the following concerning social sciences other than economics EXCEPT
A． They are "dismal" in their own way. B． They disregard the notion that both buyer and seller can benefit from a market exchange. C． They tend to make unreliable assumptions about the future. D． They rely too much on power models. E． They insufficiently account for the problem of scarcity when they make predictions.