Final answer:
In the real estate context of this question, Michelle, who is listing her house, is the 'Principal' because she is authorizing Agent Sam to act on her behalf.
Step-by-step explanation:
In the scenario provided, Michelle is seeking to list her house and has contacted Agent Sam to do so. In a real estate context, when a homeowner contracts with an agent to sell their property, the homeowner occupies the role of the principal. This is because the principal is the person who has authorized the agent to act on their behalf in transactions. On the contrary, the agent is the individual who has been given the authority to act on behalf of the principal, which would be Sam in this case. Therefore, in this relationship, regarding the listing of Michelle's house, Michelle is A) Principal.