Which of the following best describes Evercore's advisory fees?

Evercore's advisory fees primarily fund its operations, making this the best description of their fee structure. Advisory fees are a crucial source of revenue for investment banks and advisory firms like Evercore, allowing them to cover costs related to employee compensation, infrastructure, and other operational expenses. As a business model, it relies significantly on these fees as they cater to various financial services such as mergers and acquisitions, restructuring, and capital raising.

Given the context of the other choices, variable fees based on client satisfaction would imply a performance-based structure, which is not typical in advisory services where fees are often predetermined. Fixed fees regardless of services rendered do not accurately represent the flexible nature of advisory contracts that cater to the specific needs of clients, which might vary based on the complexity and scale of services provided. Lastly, stating that fees do not affect overall business strategy overlooks the critical role of revenue generation in shaping a firm's operational and strategic decisions, as financial health directly influences strategic planning and resource allocation. Thus, option C accurately captures the relationship between advisory fees and Evercore’s business functioning.