The buyer has just signed a buyer's agency agreement with a broker. The buyer has agreed to pay the broker a specific fee. Under the common law of agency, the relationship between the buyer and the broker would best be described as

"Agreement agency" is not a recognized term in agency law. While agency relationships are formed through agreements, this choice does not accurately describe the formal nature of the relationship established by a signed buyer's agency agreement.

Implied agency arises from the conduct of the parties rather than a formal agreement. In this case, the relationship is explicitly defined through a signed document, making it clear that the agency is not based on implied actions or assumptions, but rather on an explicit contract.

Gratuitous agency refers to a relationship where one party acts on behalf of another without expectation of payment or compensation. Since the buyer has agreed to pay a specific fee to the broker, this situation does not fit the definition of gratuitous agency, as there is an expectation of compensation for services rendered.