Which of the following are main components of financial modeling?

The answer focuses on the core components that constitute a comprehensive financial model. Financial modeling relies heavily on assumptions, as these drive the model's projections and scenarios. The income statement, balance sheet, and cash flow statement together provide a holistic view of a company’s financial performance, position, and cash flows, making them essential for any robust financial model.

Supporting schedules are also integral, as they provide the necessary detail and context behind the numbers reflected in the primary financial statements. These schedules can include workings for revenue breakdown, expense forecasts, or capital expenditures, facilitating a deeper analysis of the financial assumptions and enhancing the model's accuracy.

In contrast, while payroll records, tax returns, and marketing costs may be important factors in some analyses, they do not represent the foundational structure that financial models generally adhere to. The selected components in the answer encompass a complete perspective necessary for effective finance-related decision-making and analysis.