Q. Which of the following situations can be approximated to a steady state heat transfer system?

• (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at 35°C
• (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C
• (C) Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C
• (D) A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C