So-called environmentalists have argued th

问题：

So-called environmentalists have argued that the proposed Golden Lake Development would interfere with bird-migration patterns. However the fact that these same people have raised environmental objections to virtually every development proposal brought before the council in recent years indicates that their expressed concern for bird-migration patterns is nothing but a mask for their antidevelopment antiprogress agenda. Their claim therefore should be dismissed without further consideration.
Which one of the following questionable argumentative techniques is employed in the passage

A．taking the failure of a given argument to establish its conclusion as the basis for claiming that the view expressed by that conclusion is false.

B．rejecting the conclusion of an argument on the basis of a claim about the motives of those advancing the argument.

C．using a few exceptional cases as the basis for a claim about what is true in general.

D．misrepresenting evidence that supports the position the argument is intended to refute.

E．(E) assuming that what is true of a group as a whole is necessarily true of each member of that group.