Which of the following is NOT a method of terminating an agency?

The correct choice is based on an understanding of agency relationships and their termination methods. An agency can be terminated through several means, including the completion of the task for which the agency was established, the death of the principal, or mutual agreement between the principal and the agent.

When considering the options, "Completion of the agency task" is a natural endpoint for an agency relationship, as the agent's duties end once the specified task is fulfilled. The "Death of the principal" automatically terminates most agency relationships, as the principal's existence is central to the agency's authority. Similarly, "Mutual agreement" allows both parties to agree to terminate the agency, reflecting their autonomy and contractual rights.

On the other hand, "Delay in performance" does not signify the termination of the agency. It merely indicates a lag in fulfilling the tasks, which could be due to various factors such as external conditions or unanticipated challenges. As such, while delays can lead to disputes or might influence the dynamics of an agency relationship, they do not serve as a legitimate method of termination. Thus, this option stands out as the one that does not constitute a recognized method for ending an agency relationship.