Final answer:
In this scenario, Sheryl is acting as an agent. Sheryl is authorized to act on Morey's behalf and delegates the duty of collecting Morey's mail to her son, Greg.
Step-by-step explanation:
In this scenario, Sheryl is acting as an agent. An agent is a person who is authorized to act on behalf of another party, known as the principal. Sheryl undertakes the duty of collecting Morey's mail and then delegates that duty to her son, Greg. Sheryl is acting as the intermediary between Morey and Greg, and she has the authority to act on Morey's behalf.