求助：新东方理解62

Meteorologists say that if only they could design an accurate mathematical model of the atmosphere with all its complexities, they could forecast the weather with real precision. But this is an idle boast, immune to any evaluation, for any inadequate weather forecast would obviously be blamed on imperfections in the model.

Which of the following, if true, could best be used as a basis for arguing against the author's position that the meteorologists' claim cannot be evaluated?

A Certain unusual configurations of data can serve as the basis for precise weather forecasts even though the exact causal mechanisms are not understood.

B. Most significant gains in the accuracy of the relevant mathematical models are accompanied by clear gains inthe precision of weather forecasts.

C. Mathematical models of the meteorological aftermath of such catastrophic events as volcanic eruptions are beginning to be constructed.

D. Modern weather forecasts for as much as a full day ahead are broadly correct about 80 percent of the time.

E Neteirikigusts readily concede that the accurate mathematical model they are talking about is not now in their power to construct.

The answer is B, but I don't quite understand the meaning of it.