What distinguishes a principal by indispensable cooperation?

A principal by indispensable cooperation refers to an individual who plays a crucial role in the commission of a crime, providing necessary assistance or support that enables the crime to occur. This cooperation is essential for the crime to be executed, which is why the term "indispensable" is used. The individual's involvement is so significant that without it, the crime may not have taken place.

In contrast, others might have some form of involvement, but it may not be critical to the execution of the crime. For instance, someone who directly performs the crime is usually classified differently, as they fulfill the action component of the offense. A person with no legal responsibility would not contribute in a way that could implicate them in the crime at all, and someone who is merely a bystander or who arrives late does not typically engage in essential cooperation. Thus, choice C accurately captures the defining characteristic of a principal by indispensable cooperation.