Agreement of the Parties, Ratification of the Agent's Activities by the Principal

Agreement of the parties, ratification of the agent's activities by the principal, application of the doctrine of estoppel and operation of law are all:

A) ways that an agency may be established
B) ways that an agency may be sued
C) unacceptable ways to begin an agency
D) informal and thus non-binding ways of establishing an agency
E) none of the other choices are correct