Which of the following statements are TRUE?
Group of answer choices:
a. An agent's authority to act on behalf of a principal derives exclusively from the agent's express or implied authority.
b. An agent's authority must be express for the agent's act to bind a principal.
c. An agent's implied authority may be conferred by contradiction.
d. A principal's liability in a contract with a third party may depend on the authority given to the agent to enter into the contract.