Consider the graph in Figure 4, Enacted Laws as a Share of Introduced Legislation by Congress, in the tutorial. What is the best explanation for the data shown in this graph? a.) Divided government has occurred very infrequently over the past forty years. b.) Most introduced legislation has high levels of support from both parties in Congress. c.) The power and influence of political moderates in Congress is growing. d.) Increasing political polarization has diminished the legislative productivity of Congress