Consider an economy where the marginal propensity to save is 0.15; the marginal propensity to import is 0.05 and the marginal propensity to tax is 0.2. If there is an increase in government spending of $150 million, by how much would national income increase?    (a) National income would increase by $350 million (b) National income would increase by $375 million (c) National income would increase by $210 million (d) National income would increase by $240 million