Martin, who wants to sell a house he owns, authorizes his concierge, Wilhelm, to find a potential buyer, and finalize a deal above a stipulated price. Wilhelm contracts Chrisa real estate broker, and intends him to only find a potential buyer and send them over to Wilhelm for the sale. Martin then contracts ReNowait Goodhouses, a home improvement company to renovate the house ReNowait completes their work and Martin pays them. Chris then searches for a suitable buyer and finds one in George. George buys the house and Chris is paid for his services. Who is the principal during the land sale transaction $?$