These are the only two branches of government that can take the initiative to make policy.  The courts must wait for a case to be brought before it to rule on a decision that subsequently may develop policy.
 

The iron triangle theory is static in that it has only three actors involved.  It is difficult for "outsiders" to penetrate the the triangle.  Compare that to policy subsystems that have more actors and a more fluid system with actors moving in and out of the subsystem.
 

The Appropriation subcommittees are responsible for setting the amount of dollars for programs.

(A) authorization is incorrect.  These are the committees responsible for the development of the actual legislation and program from a substantive perspective.
 

While interest groups provide all of these things, information is likely the most important resource.  Congress needs interest groups to help fill the information gap that exists.  Groups need to be up front in their provision of information and not provide false information.  This could cause relationship problems between members of Congress and the groups.  Obviously, the information provided by the groups is going to be biased toward the groups presenting the information.

Remember the idea of the free rider.  Why pay a membership fee to a group like the Sierra Club, if you will obtain the benefits of a cleaner environment anyway?
 

(A) through statutory requirements is incorrect.  This is a more recent phenomenon whereby the federal government passes laws that require states to do certain things.

(B) preemption is incorrect.  This is when the national government overrides, or preempts state or local actions.