A cost sheet in cost accounting details the various cost elements for a product over a specific period or quantity. A Historical Cost Sheet uses actual past cost figures. Conversely, an Estimated Cost Sheet is based on forecasts and estimates for future production. An Estimated Cost Sheet aids management in future planning by providing insight into anticipated costs and profits. It is prepared before production begins, enabling advance planning for pricing, budgeting, and cost control. Thus, the correct answer is Estimated Cost Sheet.