Which of the following is true if an agent has no actual or apparent authority to act on behalf of a principal but the agent still enters into a contract with a third party?

a. The principal is bound, but only if the principal is a disclosed or partially disclosed principal.

b. The principal is bound, but only if the principal is an unidentified principal.

c. The principal is bound, but only if the principal is a partially disclosed principal.

d. The principal is bound, but only if the principal is a disclosed principal.

e. The principal is not bound unless the principal ratifies the contract.