Final answer:
The least intrusive intervention for a minor infraction, such as a student whispering to another student in class, would be to use an indirect cue.
Step-by-step explanation:
Based on research indicating that classroom management is most effective when interventions are as brief and unobtrusive as possible, the least intrusive intervention for a minor infraction such as a student whispering to another student would be to use an indirect cue, such as moving near the student. This intervention is less obtrusive than applying a consequence, such as time out, and still addresses the behavior by signaling to the student that their behavior should be redirected. Ignoring the behavior may not provide any guidance or feedback to the student, while a desist may be more direct and disruptive than necessary for a minor infraction.