SunLite Inc., which has recently purchased HardCast Ltd., considers switching from HardCast's worn off iron die cast moulds to investment moulds made from either plaster or mullite. Which heat transfer case applies and which of these materials (mullite or plaster) do you recommend for the mould in order to achieve the highest daily production rate? Question 7 options: mullite based on the equation for casting in insulated moulds plaster based on Chvorinov's rule plaster considering casting limited by solid-mould interface resistance resulting from an air gap mullite because of the unsteady state heat transfer in conductive iron moulds