Which of the following statements are FALSE?

Group of answer choices

a. An undisclosed principal is liable to a third party for contracts made by the agent acting within the scope of his or her authority.

b. An partially disclosed principal is liable to a third party for contracts made by the agent acting within the scope of his or her authority

c. If a principal does not ratify an authorized contract, the principal is not bound.

d. Before a principal can ratify a contract, the principal must know all of the material facts involved in the deal.