Why Does the Partisan Model of Macroeconomic Policy Predict That

Why does the partisan model of macroeconomic policy predict that changes in partisan control of the government will lead to predicable changes in fiscal policy?

A) It doesn't; the partisan model of macroeconomic policy is about whether voters are extreme or moderate. Extreme voters want redistribution and moderate voters do not.
B) Because it assumes that left wing parties represent voters who want more redistribution (and thus, higher levels of fiscal activity) and right-wing parties represent voters who want less redistribution.