Choice "B" is correct. Generally, a general agent's apparent authority does not cease unless and until notice is given. However, if the principal has received a discharge in bankruptcy, notice is not required to terminate the agent's apparent authority.
Choice "c" is incorrect. Apparent authority is based on the reasonable beliefs of the third party with whom the agent deals. Since third parties have no way of knowing whether an agency purpose has been fulfilled, notice is required to terminate agency power after fulfillment of the purpose.
Choice "a" is incorrect. Apparent authority is based on the reasonable beliefs of the third party with whom the agent deals. Since third parties have no way of knowing how long an agency is to last, notice is required to terminate agency power after the period of the agency has elapsed.
Choice "d" is incorrect. Apparent authority is based on the reasonable beliefs of the third party with whom the agent deals. Since third parties have no way of knowing whether the principal and agent have terminated their relationship, notice is required to terminate agency power after the principal and agent agree to terminate the relationship.