Final answer:
The principal broker's essential duty for supervising associated licensees is to provide training on relevant real estate laws and rules, ensuring compliance and professional standards within the firm. Hence, option (d) is correct.
Step-by-step explanation:
A principal broker is tasked with a variety of responsibilities that ultimately aim to ensure both the efficiency of the brokerage operations as well as adherence to legal and ethical standards. Among these duties, the most essential activity a principal broker would most likely be required to perform for the proper supervision of associated licensees is to train associated licensees on relevant real estate laws and rules.
This includes making sure that associates are up-to-date with the latest regulations, understand their obligations under the law, and conduct business in a manner that is compliant with state and federal real estate statutes. Such training not only upholds professional standards within the firm but also mitigates the risk of legal issues that could arise from non-compliance.