Final answer:
The broker is not required to reveal the occupation of the third party, as it may breach confidentiality. Age, address, and phone number are generally considered contact information and may be shared under certain agreements.
Step-by-step explanation:
A broker may have access to certain confidential information about a third party that cannot be revealed, even upon request from the principal. Among the options provided, the one that a broker is not required to reveal is the third party's occupation. Disclosing the occupation could potentially lead to the identification of the third party in a way that may breach confidentiality or privacy standards, especially if the occupation is unique or provides a substantial amount of information about the individual. The age, address, and phone number could be considered contact information, which might be necessary for the principal to have in order to engage in the transaction. However, the necessity to disclose such information is dependent upon the agreement between the broker and the principal, as well as privacy laws and professional standards.