Answer: The Estoppel Doctrine.
The Estoppel doctrine is a principle that was established in Pickar vs. Sears case. According to this principle, if a person intentionally induces the other person to believe and act upon such representation, this person cannot deny the truth in subsequent court proceedings. This principle is used to prevent a person from being wronged by the inconsistencies of other person's words and actions. Thus, in this situation, we can say that the Estoppel Doctrine is the one that applies since Kennie provided agency tasks for Buzz and can NOT disavow that behavior.