4. Imagine an economy in which the government spent all its tax revenues but was prevented by a balanced budget amendment from spending any more. Thus, G=tY. You can answer the questions below without explicitly solving a model. a. Explain why government spending is an endogenous variable in this model. b. Is the expenditure multiplier larger or smaller than the case in which government spending is exogenous? Is this a good thing or a bad thing? c. .When t increases, does Y increase, decrease or remain the same? Explain..