Which of the Following Explains Why Pork-Barrel Spending Is Often

Which of the following explains why pork-barrel spending is often approved, even when the spending is inefficient?

A) Each representative has little incentive to oppose pork-barrel spending since the tax savings would accrue to taxpayers throughout the nation.
B) General opposition to pork-barrel spending by a legislator would make it more difficult for the legislator to arrange for pork-barrel projects that provide concentrated benefits for his district.
C) Logrolling increases the likelihood that pork-barrel projects will be approved.
D) All of the above are correct.