C is the answer.
In the passage, the Mayor does not address directly the issue of whether the factory could cause health problems. He simply rejects the claim by saying that the protestors were there only because they were paid, by does not rule out the possibility that it could cause health problems.
Mayor: A huge protest against plans to build a chemical plant in this town was held yesterday. The protesters claim that the factory could cause health problems. But this worry can be dismissed. Most of the protesters were there only because they were paid to show up by property developers who are concerned that the factory would lower the value of nearby land that they own.
Which one of the flowing most accurately expresses a flaw in reasoning in the mayor's argument?
(A) The argument characterizes an opposing view and then attacks this characterized view
(B) The argument attempts to persuade by inducing fear of the consequences of rejecting its conclusion
(C) The argument rejects a claim simply because of the motivation that some people have for make it
(D) The argument generalizes on the basis of a few unrepresentative cases
(E) The argument mistakes a claim that a result is possible for a claim that the result is inevitable