As defined by Virginia law, ______ is any person, or business entity of not more than two persons unless related by blood or marriage, who for compensation or valuable consideration is employed either directly or indirectly by, or affiliated as an independent contractor with, a real estate broker, to sell or offer to sell, or to buy or offer to buy, or to negotiate the purchase, sale or exchange of real estate, or to lease, rent or offer for rent any real estate, or to negotiate leases, or of the improvements relating to the real estate.