Which of the following statements correctly describes a disadvantage of using a zero-based budgeting system? The annual review needed to implement a zero-based budgeting system A. can be very time consuming and expensive. B. A zero-based budgeting system is based on a set of assumptions that may not come true. If a project uses resources that are used in other areas of the organization, a C. zero-based budgeting system may not give an accurate estimate of its costs. A zero-based budgeting system is only useful for control purposes, not planning purposes