Final answer:
Robert is practicing the ethos of transparency by requesting a detailed report of fundraiser expenses, which is a best practice for nonprofit boards as recommended by Board Source.
Step-by-step explanation:
When Robert, the chair of a nonprofit board of directors, asks the CEO to provide an accurate report of the expenses incurred for a fundraiser, he is practicing the ethos of transparency. This is one of the best practices recommended by Board Source for nonprofit boards. An ethos of transparency involves open and honest communication about the organization's operations, which includes financial disclosures. By requesting an accurate expenses report, Robert is ensuring that the board has the necessary information to oversee the organization effectively and maintain accountability to stakeholders.