Edward Leaves Sarah, the Cashier, in Charge of His Gasoline

Edward leaves Sarah, the cashier, in charge of his gasoline service station while he goes home to have lunch. He tells her not to accept any auto repair jobs. During the lunch break, a customer leaves his car with Sarah to be serviced for a minor engine problem. When Edward returns, he accepts the repair job. Which of the following types of agency relationship is most likely to have been formed here?

A) agency by implied authority
B) expressed agency
C) agency by estoppel
D) agency by ratification