What is the first step that commences a criminal prosecution?

The correct response highlights the filing of an accusatory instrument as the initial step in commencing a criminal prosecution. An accusatory instrument is a legal document that formally charges an individual with a crime, initiating the process in the judicial system. This document sets forth the specifics of the offense and the defendant, thus formally notifying the accused of the charges against them.

In many jurisdictions, the filing of a complaint or other documents such as indictments generally are subsequent steps that follow the submission of the accusatory instrument. A complaint can be seen as a type of accusatory instrument; however, the term "accusatory instrument" encompasses various formal charging documents, which is broader and includes different forms suitable to the jurisdiction's legal framework.

The scheduling of a hearing will occur after the accusatory instrument has been filed, meaning it is not a preliminary step in the prosecution process. Understanding this sequence is essential for grasping how criminal procedures unfold legally.