The practice to use steam on the shell side and water on the tube side in condensers of steam power plant is because
(a) to increase overall HT coefficient, water side velocity can be increased if water is on the tube side
(b) condenser can act as a storage unit for condensed steam
(c) rate of condensation of steam is invariably smaller than the mass flow rate of cooling water
(d) it is easier to maintain vacuum on the shell side than on the tube side