A stainless steel tube ( Ks = 19 W/mK) of a 2cm ID and 5 cm OD is insulated with 3 cm thick asbestos (Ka = 0.2 W/mK). If the temperature difference between the innermost and outermost surface is 600C, the heat transfer rate per unit length is
(a) 0.94 W/m (b) 9.44 W/m
(c) 944.72 W/m (d) 9447.21 W/m