Which of the Following Helps Explain Pork-Barrel Activities in Congress

Which of the following helps explain pork-barrel activities in Congress?

A) the rationality principle, because incumbent legislators think funding all these projects is in the best interest of the nation for the federal government
B) the collective action principle, because legislators must join with other legislators in exchanging support for each other's projects
C) the institution principle, because the institutions of Congress are designed to prevent distributive practices such as pork-barrel legislation
D) the policy principle, because pork-barrel legislation is Congress's primary tool for improving the national economy