Which of the Following Statements Best Defines Customary Authority

Which of the following statements best defines customary authority?

A) It is the authority specifically delegated to an agent by the agreement creating the agency.
B) It is the authority to do things not specifically listed in a contract so that the purpose of the agency can be fulfilled.
C) It is the authority to act on behalf of another that arises when such agents ordinarily possess such powers.
D) It is the authority that an agent is believed to have because of the principal's behavior.