Which definition listed below refers to the Apportion Method? a. Uses a Top-Down approach to obtain an estimate of the total cost of the project. b. Estimates the time needed to produce a given level of output, such as specific data files, interfaces and inquiries answered. c. Indicates a pattern of time reduction as a task that is continually repeated. d. Employs a known parameter and applies this to a known variable to obtain an estimate of the total cost