In the Context of Public Policy, What Effect Does a Trigger

In the context of public policy, what effect does a trigger mechanism have?

A) It compels the legislative branch to begin the process of reauthorization and investigation.
B) It forces the executive branch to implement, or "pull the trigger on," a new policy.
C) It propels an established problem on to the next stage of the policy process.
D) It provides a legitimate way to exclude an item from an agenda.