What Allows Iron Triangles and Captured Agencies to Survive

What allows iron triangles and captured agencies to survive?

A) the fact that Congress is fairly lax about engaging in oversight in many areas of public policy
B) keeping the costs they impose on everyone small enough to avoid attracting serious attention from political entrepreneurs in Congress or the White House who may be scouting for popular issues to champion
C) keeping the benefits they provide generous enough to avoid attracting the scouting of political entrepreneurs in Congress or the White House who may be scouting for programs to cut
D) the fact that most Americans do not care about the government as long as they receive their benefits in a timely manner