Final answer:
An agent can bind his principal on a contract or other matter only when the agent has authority to do so.
Step-by-step explanation:
The correct answer is d. Authority.
An agent can bind his principal on a contract or other matter only when the agent has authority to do so. Authority refers to the power or right to act on behalf of someone else and make legally binding decisions. Without authority, the agent cannot create legal obligations or contracts for the principal.
For example, in an employer-employee relationship, the employee may have the authority to enter into contracts on behalf of the employer if it is within the scope of their job responsibilities. However, if the employee exceeds their authority, the contract may not be binding on the employer.