Which party is most likely not entitled to sue for commission earned in a Maryland real estate transaction?

• A. Mario, an unlicensed assistant who filled in for Todd and showed a buyer
• B. Theresa, the buyer, whose case involved a salesperson who was not paid a commission
• C. Tatum, a licensed assistant who acted as a sub-agent for her broker's seller client and hosted several open houses
• D. Zander, a broker who procured a list-price buyer for his seller client, but the seller declined the offer and cancelled the listing

Answer: (A)