GMAT Critical Reasoning (CR) | Re: CR Revision: The United States government uses only a household’s cash

Any answer choice which says that the Government's calculation method is flawed and needs to be revised is the answer. "C" brings out a discrepancy. Established that means accepted research studies by private sectors indicates that the figure is less than the figure indicated by the Government's study. Since multiple studies made by the private sector give a different figure, there has to be some defect in the Government's calculation method